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Hyun Lee K, Kimoto M, Kawai G, Okamoto I, Fin A, Hirao I. Dye‐Conjugated Spinach RNA by Genetic Alphabet Expansion. Chemistry 2022; 28:e202104396. [DOI: 10.1002/chem.202104396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Indexed: 11/09/2022]
Affiliation(s)
- Kyung Hyun Lee
- Institute of Bioengineering and Bioimaging A*STAR 31 Biopolis Way, The Nanos #07-01 Singapore 138669 Singapore
| | - Michiko Kimoto
- Institute of Bioengineering and Bioimaging A*STAR 31 Biopolis Way, The Nanos #07-01 Singapore 138669 Singapore
| | - Gota Kawai
- Chiba Institute of Technology (CIT) Tsudanuma 2-17-1 Narashino Chiba 275-0016 Japan
| | - Itaru Okamoto
- Institute of Bioengineering and Bioimaging A*STAR 31 Biopolis Way, The Nanos #07-01 Singapore 138669 Singapore
| | - Andrea Fin
- Institute of Bioengineering and Bioimaging A*STAR 31 Biopolis Way, The Nanos #07-01 Singapore 138669 Singapore
| | - Ichiro Hirao
- Institute of Bioengineering and Bioimaging A*STAR 31 Biopolis Way, The Nanos #07-01 Singapore 138669 Singapore
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2
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Cao H, Wang Y, Zhang N, Xia S, Tian P, Lu L, Du J, Du Y. Progress of CRISPR-Cas13 Mediated Live-Cell RNA Imaging and Detection of RNA-Protein Interactions. Front Cell Dev Biol 2022; 10:866820. [PMID: 35356276 PMCID: PMC8959342 DOI: 10.3389/fcell.2022.866820] [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: 01/31/2022] [Accepted: 02/21/2022] [Indexed: 12/26/2022] Open
Abstract
Ribonucleic acid (RNA) and proteins play critical roles in gene expression and regulation. The relevant study increases the understanding of various life processes and contributes to the diagnosis and treatment of different diseases. RNA imaging and mapping RNA-protein interactions expand the understanding of RNA biology. However, the existing methods have some limitations. Recently, precise RNA targeting of CRISPR-Cas13 in cells has been reported, which is considered a new promising platform for RNA imaging in living cells and recognition of RNA-protein interactions. In this review, we first described the current findings on Cas13. Furthermore, we introduced current tools of RNA real-time imaging and mapping RNA-protein interactions and highlighted the latest advances in Cas13-mediated tools. Finally, we discussed the advantages and disadvantages of Cas13-based methods, providing a set of new ideas for the optimization of Cas13-mediated methods.
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Affiliation(s)
- Huake Cao
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Yuechen Wang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- Second School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Ning Zhang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
- First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Siyuan Xia
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- Second School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Pengfei Tian
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
- First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Li Lu
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Juan Du
- School of Medicine, The Chinese University of Hong Kong, Shenzhen, China
- Longgang District People’s Hospital of Shenzhen & The Second Affiliated Hospital, The Chinese University of Hong Kong, Shenzhen, China
- *Correspondence: Yinan Du, ; Juan Du,
| | - Yinan Du
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- *Correspondence: Yinan Du, ; Juan Du,
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3
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Bai J, Luo Y, Wang X, Li S, Luo M, Yin M, Zuo Y, Li G, Yao J, Yang H, Zhang M, Wei W, Wang M, Wang R, Fan C, Zhao Y. A protein-independent fluorescent RNA aptamer reporter system for plant genetic engineering. Nat Commun 2020; 11:3847. [PMID: 32737299 PMCID: PMC7395781 DOI: 10.1038/s41467-020-17497-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 07/02/2020] [Indexed: 02/05/2023] Open
Abstract
Reporter systems are routinely used in plant genetic engineering and functional genomics research. Most such plant reporter systems cause accumulation of foreign proteins. Here, we demonstrate a protein-independent reporter system, 3WJ-4 × Bro, based on a fluorescent RNA aptamer. Via transient expression assays in both Escherichia coli and Nicotiana benthamiana, we show that 3WJ-4 × Bro is suitable for transgene identification and as an mRNA reporter for expression pattern analysis. Following stable transformation in Arabidopsis thaliana, 3WJ-4 × Bro co-segregates and co-expresses with target transcripts and is stably inherited through multiple generations. Further, 3WJ-4 × Bro can be used to visualize virus-mediated RNA delivery in plants. This study demonstrates a protein-independent reporter system that can be used for transgene identification and in vivo dynamic analysis of mRNA.
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Affiliation(s)
- Jiuyuan Bai
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Yao Luo
- State Key Laboratory and Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Xin Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Shi Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Mei Luo
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Meng Yin
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Yuanli Zuo
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Guolin Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Junyu Yao
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Hua Yang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Mingdi Zhang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Wei Wei
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Maolin Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Rui Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China.
| | - Chunhai Fan
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China.
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acids Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China.
| | - Yun Zhao
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China.
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5
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Samanta D, Ebrahimi SB, Mirkin CA. Nucleic-Acid Structures as Intracellular Probes for Live Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1901743. [PMID: 31271253 PMCID: PMC6942251 DOI: 10.1002/adma.201901743] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/08/2019] [Indexed: 05/02/2023]
Abstract
The chemical composition of cells at the molecular level determines their growth, differentiation, structure, and function. Probing this composition is powerful because it provides invaluable insight into chemical processes inside cells and in certain cases allows disease diagnosis based on molecular profiles. However, many techniques analyze fixed cells or lysates of bulk populations, in which information about dynamics and cellular heterogeneity is lost. Recently, nucleic-acid-based probes have emerged as a promising platform for the detection of a wide variety of intracellular analytes in live cells with single-cell resolution. Recent advances in this field are described and common strategies for probe design, types of targets that can be identified, current limitations, and future directions are discussed.
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Affiliation(s)
- Devleena Samanta
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Sasha B Ebrahimi
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Chad A Mirkin
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
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6
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A dimerization-based fluorogenic dye-aptamer module for RNA imaging in live cells. Nat Chem Biol 2019; 16:69-76. [PMID: 31636432 PMCID: PMC6920041 DOI: 10.1038/s41589-019-0381-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 08/22/2019] [Indexed: 01/19/2023]
Abstract
Live-cell imaging of RNA has remained a challenge because of the lack of naturally fluorescent RNAs. Recently developed RNA aptamers that can light-up small fluorogenic dyes could overcome this limitation, but they still suffer from poor brightness and photostability. Here, we propose a concept of cell-permeable fluorogenic dimer of sulforhodamine B dyes (Gemini-561) and corresponding dimerized aptamer (o-Coral) that can drastically enhance performance of the current RNA imaging method. The unprecedented brightness and photostability together with high affinity of this complex allowed, for the first time, direct fluorescence imaging in live mammalian cells of RNA polymerase-III transcription products as well as messenger RNAs labelled with a single copy of the aptamer, i.e. without tag multimerization. The developed fluorogenic module enables fast and sensitive detection of RNA inside live cells, while the proposed design concept opens the route to new generation of ultrabright RNA probes.
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7
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Skruzny M, Pohl E, Abella M. FRET Microscopy in Yeast. BIOSENSORS 2019; 9:E122. [PMID: 31614546 PMCID: PMC6956097 DOI: 10.3390/bios9040122] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/19/2019] [Accepted: 09/30/2019] [Indexed: 02/06/2023]
Abstract
Förster resonance energy transfer (FRET) microscopy is a powerful fluorescence microscopy method to study the nanoscale organization of multiprotein assemblies in vivo. Moreover, many biochemical and biophysical processes can be followed by employing sophisticated FRET biosensors directly in living cells. Here, we summarize existing FRET experiments and biosensors applied in yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, two important models of fundamental biomedical research and efficient platforms for analyses of bioactive molecules. We aim to provide a practical guide on suitable FRET techniques, fluorescent proteins, and experimental setups available for successful FRET experiments in yeasts.
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Affiliation(s)
- Michal Skruzny
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany.
| | - Emma Pohl
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany
| | - Marc Abella
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany
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8
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Zinskie JA, Roig M, Janetopoulos C, Myers KA, Bruist MF. Live-cell imaging of small nucleolar RNA tagged with the broccoli aptamer in yeast. FEMS Yeast Res 2019; 18:5078348. [PMID: 30137288 DOI: 10.1093/femsyr/foy093] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 08/20/2018] [Indexed: 11/14/2022] Open
Abstract
The development of the RNA 'vegetable' aptamers, Spinach and Broccoli, has simplified RNA imaging, especially in live cells. These RNA aptamers interact with a fluorophore (DFHBI or DFHBI-1T) to produce a green fluorescence signal. Although used in mammalian and Escherichia coli cells, the use of these aptamers in yeast has been limited. Here we describe how the Saccharomyces cerevisiae snoRNA, snR30, was tagged with the Spinach or the Broccoli aptamers and observed in live cells. The ability to observe aptamer fluorescence in polyacrylamide gels stained with a fluorophore or with a microplate reader can ease preliminary screening of the aptamers in different RNA scaffolds. In snR30 a tandem repeat of the Broccoli aptamer produced the best signal in vitro. Multiple factors in cell preparation were vital for obtaining a good fluorescence signal. These factors included the clearance of the native unmodified snR30, the amount and length of dye incubation and the rinsing of cells. In cells, the aptamers did not interfere with the structure or essential function of snR30, as the tagged RNA localized to the nucleolus and directed processing of ribosomal RNA in yeast. High-resolution images of the tagged snoRNA were obtained with live cells immobilized by a microcompressor.
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Affiliation(s)
- Jessica A Zinskie
- University of the Sciences, Department of Chemistry & Biochemistry, 600 S. 43rd St., Philadelphia, PA 19104.,Rowan University, School of Osteopathic Medicine, Department of Cell Biology and Neuroscience, 2 Medical Center Dr., Stratford, NJ 08084
| | - Meghan Roig
- University of the Sciences, Department of Chemistry & Biochemistry, 600 S. 43rd St., Philadelphia, PA 19104.,Florida International University, Department of Biochemistry and Biochemistry, 11200 SW 8th St., Miami, FL 33199
| | | | - Kenneth A Myers
- University of the Sciences, Department of Biological Sciences, Philadelphia, PA 19104
| | - Michael F Bruist
- University of the Sciences, Department of Chemistry & Biochemistry, 600 S. 43rd St., Philadelphia, PA 19104
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Karunanayake Mudiyanselage APKK, Wu R, Leon-Duque MA, Ren K, You M. "Second-generation" fluorogenic RNA-based sensors. Methods 2019; 161:24-34. [PMID: 30660865 PMCID: PMC6589113 DOI: 10.1016/j.ymeth.2019.01.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/11/2019] [Accepted: 01/13/2019] [Indexed: 02/07/2023] Open
Abstract
A fluorogenic aptamer can specifically interact with a fluorophore to activate its fluorescence. These nucleic acid-based fluorogenic modules have been dramatically developed over the past decade, and have been used as versatile reporters in the sensor development and for intracellular imaging. In this review, we summarize the design principles, applications, and challenges of the first-generation fluorogenic RNA-based sensors. Moreover, we discuss some strategies to develop next-generation biosensors with improved sensitivity, selectivity, quantification property, and eukaryotic robustness. Using genetically encoded catalytic hairpin assembly strategy as an example, we further introduce a standard protocol to design, characterize, and apply these fluorogenic RNA-based sensors for in vitro detection and cellular imaging of target biomolecules. By incorporating natural RNA machineries, nucleic acid nanotechnology, and systematic evolution approaches, next-generation fluorogenic RNA-based devices can be potentially engineered to be widely applied in cell biology and biomedicine.
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Affiliation(s)
| | - Rigumula Wu
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Mark A Leon-Duque
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Kewei Ren
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Mingxu You
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA.
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Neubacher S, Hennig S. RNA Structure and Cellular Applications of Fluorescent Light-Up Aptamers. Angew Chem Int Ed Engl 2019; 58:1266-1279. [PMID: 30102012 PMCID: PMC6391945 DOI: 10.1002/anie.201806482] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Indexed: 12/16/2022]
Abstract
The cellular functions of RNA are not limited to their role as blueprints for protein synthesis. In particular, noncoding RNA, such as, snRNAs, lncRNAs, miRNAs, play important roles. With increasing numbers of RNAs being identified, it is well known that the transcriptome outnumbers the proteome by far. This emphasizes the great importance of functional RNA characterization and the need to further develop tools for these investigations, many of which are still in their infancy. Fluorescent light-up aptamers (FLAPs) are RNA sequences that can bind nontoxic, cell-permeable small-molecule fluorogens and enhance their fluorescence over many orders of magnitude upon binding. FLAPs can be encoded on the DNA level using standard molecular biology tools and are subsequently transcribed into RNA by the cellular machinery, so that they can be used as fluorescent RNA tags (FLAP-tags). In this Minireview, we give a brief overview of the fluorogens that have been developed and their binding RNA aptamers, with a special focus on published crystal structures. A summary of current and future cellular FLAP applications with an emphasis on the study of RNA-RNA and RNA-protein interactions using split-FLAP and Förster resonance energy transfer (FRET) systems is given.
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Affiliation(s)
- Saskia Neubacher
- Department of Chemistry & Pharmaceutical SciencesVU University AmsterdamDe Boelelaan 11081081HZAmsterdamThe Netherlands
| | - Sven Hennig
- Department of Chemistry & Pharmaceutical SciencesVU University AmsterdamDe Boelelaan 11081081HZAmsterdamThe Netherlands
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11
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Neubacher S, Hennig S. RNA Structure and Cellular Applications of Fluorescent Light-Up Aptamers. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201806482] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Saskia Neubacher
- Department of Chemistry & Pharmaceutical Sciences; VU University Amsterdam; De Boelelaan 1108 1081 HZ Amsterdam The Netherlands
| | - Sven Hennig
- Department of Chemistry & Pharmaceutical Sciences; VU University Amsterdam; De Boelelaan 1108 1081 HZ Amsterdam The Netherlands
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12
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Aptamer-enabled uptake of small molecule ligands. Sci Rep 2018; 8:15712. [PMID: 30356136 PMCID: PMC6200808 DOI: 10.1038/s41598-018-33887-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 10/03/2018] [Indexed: 11/08/2022] Open
Abstract
The relative ease of isolating aptamers with high specificity for target molecules suggests that molecular recognition may be common in the folds of natural RNAs. We show here that, when expressed in cells, aptamers can increase the intracellular concentrations of their small molecule ligands. We have named these aptamers as DRAGINs (Drug Binding Aptamers for Growing Intracellular Numbers). The DRAGIN property, assessed here by the ability to enhance the toxicity of their ligands, was found for some, but not all, aminoglycoside aptamers. One aptamer protected cells against killing by its ligand. Another aptamer promoted killing as a singlemer and protected against killing as a tandemer. Based on a mathematical model, cell protection vs. killing is proposed as governed by aptamer affinity and access to the inner surface of the cell membrane, with the latter being a critical determinant. With RNA molecules proposed as the earliest functional polymers to drive the evolution of life, we suggest that RNA aptamer-like structures present in primitive cells might have selectively concentrated precursors for polymer synthesis. Riboswitches may be the evolved forms of these ancient aptamer-like “nutrient procurers”. Aptamers with DRAGIN capability in the modern world could be applied for imaging cells, in synthetic cell constructs, or to draw drugs into cells to make “undruggable” targets accessible to small molecule inhibitors.
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Development of a genetically encodable FRET system using fluorescent RNA aptamers. Nat Commun 2018; 9:18. [PMID: 29295996 PMCID: PMC5750238 DOI: 10.1038/s41467-017-02435-x] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 11/30/2017] [Indexed: 12/21/2022] Open
Abstract
Fluorescent RNA aptamers are useful as markers for tracking RNA molecules inside cells and for creating biosensor devices. Förster resonance energy transfer (FRET) based on fluorescent proteins has been used to detect conformational changes, however, such FRET devices have not yet been produced using fluorescent RNA aptamers. Here we develop an RNA aptamer-based FRET (apta-FRET) system using single-stranded RNA origami scaffolds. To obtain FRET, the fluorescent aptamers Spinach and Mango are placed in close proximity on the RNA scaffolds and a new fluorophore is synthesized to increase spectral overlap. RNA devices that respond to conformational changes are developed, and finally, apta-FRET constructs are expressed in E. coli where FRET is observed, demonstrating that the apta-FRET system is genetically encodable and that the RNA nanostructures fold correctly in bacteria. We anticipate that the RNA apta-FRET system could have applications as ratiometric sensors for real-time studies in cell and synthetic biology. FRET has been used to study protein conformational changes but has never been applied to RNA aptamers. Here the authors develop a genetically encodable RNA aptamer-based FRET system on single-stranded RNA origami scaffolds, and demonstrate it can be used to study RNA conformational changes.
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Bouhedda F, Autour A, Ryckelynck M. Light-Up RNA Aptamers and Their Cognate Fluorogens: From Their Development to Their Applications. Int J Mol Sci 2017; 19:ijms19010044. [PMID: 29295531 PMCID: PMC5795994 DOI: 10.3390/ijms19010044] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 12/31/2022] Open
Abstract
An RNA-based fluorogenic module consists of a light-up RNA aptamer able to specifically interact with a fluorogen to form a fluorescent complex. Over the past decade, significant efforts have been devoted to the development of such modules, which now cover the whole visible spectrum, as well as to their engineering to serve in a wide range of applications. In this review, we summarize the different strategies used to develop each partner (the fluorogen and the light-up RNA aptamer) prior to giving an overview of their applications that range from live-cell RNA imaging to the set-up of high-throughput drug screening pipelines. We then conclude with a critical discussion on the current limitations of these modules and how combining in vitro selection with screening approaches may help develop even better molecules.
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Affiliation(s)
- Farah Bouhedda
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, UPR 9002, F-67000 Strasbourg, France.
| | - Alexis Autour
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, UPR 9002, F-67000 Strasbourg, France.
| | - Michael Ryckelynck
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, UPR 9002, F-67000 Strasbourg, France.
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Decoene T, De Paepe B, Maertens J, Coussement P, Peters G, De Maeseneire SL, De Mey M. Standardization in synthetic biology: an engineering discipline coming of age. Crit Rev Biotechnol 2017; 38:647-656. [PMID: 28954542 DOI: 10.1080/07388551.2017.1380600] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Leaping DNA read-and-write technologies, and extensive automation and miniaturization are radically transforming the field of biological experimentation by providing the tools that enable the cost-effective high-throughput required to address the enormous complexity of biological systems. However, standardization of the synthetic biology workflow has not kept abreast with dwindling technical and resource constraints, leading, for example, to the collection of multi-level and multi-omics large data sets that end up disconnected or remain under- or even unexploited. PURPOSE In this contribution, we critically evaluate the various efforts, and the (limited) success thereof, in order to introduce standards for defining, designing, assembling, characterizing, and sharing synthetic biology parts. The causes for this success or the lack thereof, as well as possible solutions to overcome these, are discussed. CONCLUSION Akin to other engineering disciplines, extensive standardization will undoubtedly speed-up and reduce the cost of bioprocess development. In this respect, further implementation of synthetic biology standards will be crucial for the field in order to redeem its promise, i.e. to enable predictable forward engineering.
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Affiliation(s)
- Thomas Decoene
- a Centre for Synthetic Biology, Ghent University , Ghent , Belgium
| | - Brecht De Paepe
- a Centre for Synthetic Biology, Ghent University , Ghent , Belgium
| | - Jo Maertens
- a Centre for Synthetic Biology, Ghent University , Ghent , Belgium
| | | | - Gert Peters
- a Centre for Synthetic Biology, Ghent University , Ghent , Belgium
| | - Sofie L De Maeseneire
- b InBio.be, Centre for Industrial Biotechnology and Biocatalysis, Ghent University , Ghent , Belgium
| | - Marjan De Mey
- a Centre for Synthetic Biology, Ghent University , Ghent , Belgium
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Rau K, Rentmeister A. Making the Message Clear: Concepts for mRNA Imaging. ACS CENTRAL SCIENCE 2017; 3:701-707. [PMID: 28776011 PMCID: PMC5532709 DOI: 10.1021/acscentsci.7b00251] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Indexed: 05/13/2023]
Abstract
The transcriptome of each individual cell contains numerous RNA species, each of which can be controlled by multiple mechanisms during their lifetime. The standard transcriptome analysis focuses on the expression levels of the genes of interest. To gain additional insights into spatiotemporal RNA distribution and the underlying trafficking processes, RNA labeling and imaging are necessary-ideally in living cells. This perspective will summarize state-of-the-art RNA imaging methods including their strengths and weaknesses.
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Affiliation(s)
| | - Andrea Rentmeister
- Cells-in-Motion Cluster of Excellence
(EXC1003-CiM), University of Münster, Germany. E-mail:
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17
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van Gijtenbeek LA, Kok J. Illuminating Messengers: An Update and Outlook on RNA Visualization in Bacteria. Front Microbiol 2017; 8:1161. [PMID: 28690601 PMCID: PMC5479882 DOI: 10.3389/fmicb.2017.01161] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 06/07/2017] [Indexed: 01/04/2023] Open
Abstract
To be able to visualize the abundance and spatiotemporal features of RNAs in bacterial cells would permit obtaining a pivotal understanding of many mechanisms underlying bacterial cell biology. The first methods that allowed observing single mRNA molecules in individual cells were introduced by Bertrand et al. (1998) and Femino et al. (1998). Since then, a plethora of techniques to image RNA molecules with the aid of fluorescence microscopy has emerged. Many of these approaches are useful for the large eukaryotic cells but their adaptation to study RNA, specifically mRNA molecules, in bacterial cells progressed relatively slow. Here, an overview will be given of fluorescent techniques that can be used to reveal specific RNA molecules inside fixed and living single bacterial cells. It includes a critical evaluation of their caveats as well as potential solutions.
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Affiliation(s)
- Lieke A van Gijtenbeek
- Department of Molecular Genetics, Faculty of Science and Engineering, University of GroningenGroningen, Netherlands
| | - Jan Kok
- Department of Molecular Genetics, Faculty of Science and Engineering, University of GroningenGroningen, Netherlands
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18
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Xia Y, Zhang R, Wang Z, Tian J, Chen X. Recent advances in high-performance fluorescent and bioluminescent RNA imaging probes. Chem Soc Rev 2017; 46:2824-2843. [PMID: 28345687 PMCID: PMC5472208 DOI: 10.1039/c6cs00675b] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
RNA plays an important role in life processes. Imaging of messenger RNAs (mRNAs) and micro-RNAs (miRNAs) not only allows us to learn the formation and transcription of mRNAs and the biogenesis of miRNAs involved in various life processes, but also helps in detecting cancer. High-performance RNA imaging probes greatly expand our view of life processes and enhance the cancer detection accuracy. In this review, we summarize the state-of-the-art high-performance RNA imaging probes, including exogenous probes that can image RNA sequences with special modification and endogeneous probes that can directly image endogenous RNAs without special treatment. For each probe, we review its structure and imaging principle in detail. Finally, we summarize the application of mRNA and miRNA imaging probes in studying life processes as well as in detecting cancer. By correlating the structures and principles of various probes with their practical uses, we compare different RNA imaging probes and offer guidance for better utilization of the current imaging probes and the future design of higher-performance RNA imaging probes.
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Affiliation(s)
- Yuqiong Xia
- Engineering Research Center of Molecular-imaging and Neuro-imaging of Ministry of Education, School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710126, China.
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19
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Perez-Gonzalez C, Lafontaine DA, Penedo JC. Fluorescence-Based Strategies to Investigate the Structure and Dynamics of Aptamer-Ligand Complexes. Front Chem 2016; 4:33. [PMID: 27536656 PMCID: PMC4971091 DOI: 10.3389/fchem.2016.00033] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 07/11/2016] [Indexed: 12/11/2022] Open
Abstract
In addition to the helical nature of double-stranded DNA and RNA, single-stranded oligonucleotides can arrange themselves into tridimensional structures containing loops, bulges, internal hairpins and many other motifs. This ability has been used for more than two decades to generate oligonucleotide sequences, so-called aptamers, that can recognize certain metabolites with high affinity and specificity. More recently, this library of artificially-generated nucleic acid aptamers has been expanded by the discovery that naturally occurring RNA sequences control bacterial gene expression in response to cellular concentration of a given metabolite. The application of fluorescence methods has been pivotal to characterize in detail the structure and dynamics of these aptamer-ligand complexes in solution. This is mostly due to the intrinsic high sensitivity of fluorescence methods and also to significant improvements in solid-phase synthesis, post-synthetic labeling strategies and optical instrumentation that took place during the last decade. In this work, we provide an overview of the most widely employed fluorescence methods to investigate aptamer structure and function by describing the use of aptamers labeled with a single dye in fluorescence quenching and anisotropy assays. The use of 2-aminopurine as a fluorescent analog of adenine to monitor local changes in structure and fluorescence resonance energy transfer (FRET) to follow long-range conformational changes is also covered in detail. The last part of the review is dedicated to the application of fluorescence techniques based on single-molecule microscopy, a technique that has revolutionized our understanding of nucleic acid structure and dynamics. We finally describe the advantages of monitoring ligand-binding and conformational changes, one molecule at a time, to decipher the complexity of regulatory aptamers and summarize the emerging folding and ligand-binding models arising from the application of these single-molecule FRET microscopy techniques.
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Affiliation(s)
- Cibran Perez-Gonzalez
- Laboratory for Biophysics and Biomolecular Dynamics, SUPA School of Physics and Astronomy, University of St. AndrewsSt Andrews, UK
| | - Daniel A. Lafontaine
- RNA Group, Department of Biology, Faculty of Science, Université de SherbrookeSherbrooke, QC, Canada
| | - J. Carlos Penedo
- Laboratory for Biophysics and Biomolecular Dynamics, SUPA School of Physics and Astronomy, University of St. AndrewsSt Andrews, UK
- Laboratory for Biophysics and Biomolecular Dynamics, Biomedical Sciences Research Complex, School of Biology, University of St. AndrewsSt. Andrews, UK
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20
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Abstract
Seeing is not only believing; it also includes understanding. Cellular imaging with GFP in live cells has been transformative in many research fields. Modulation of cellular regulation is tightly regulated and innovative imaging technologies contribute to further understand cellular signaling and physiology. New types of genetically encoded biosensors have been developed over the last decade. They are RNA aptamers that bind with their cognate fluorogen ligands and activate their fluorescence. The emergence and the evolution of these RNA aptamers as well as their conversion into a wide spectrum of applications are examined in a global way.
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Affiliation(s)
- Jonathan Ouellet
- Department of Chemistry and Physics, Monmouth UniversityWest Long Branch, NJ, USA
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21
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Pfeiffer F, Mayer G. Selection and Biosensor Application of Aptamers for Small Molecules. Front Chem 2016; 4:25. [PMID: 27379229 PMCID: PMC4908669 DOI: 10.3389/fchem.2016.00025] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 05/30/2016] [Indexed: 12/12/2022] Open
Abstract
Small molecules play a major role in the human body and as drugs, toxins, and chemicals. Tools to detect and quantify them are therefore in high demand. This review will give an overview about aptamers interacting with small molecules and their selection. We discuss the current state of the field, including advantages as well as problems associated with their use and possible solutions to tackle these. We then discuss different kinds of small molecule aptamer-based sensors described in literature and their applications, ranging from detecting drinking water contaminations to RNA imaging.
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Affiliation(s)
- Franziska Pfeiffer
- Department of Chemical Biology, Life and Medical Sciences Institute, University of Bonn Bonn, Germany
| | - Günter Mayer
- Department of Chemical Biology, Life and Medical Sciences Institute, University of Bonn Bonn, Germany
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22
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Ray J, Shin I, Ilgu M, Bendickson L, Gupta V, Kraus GA, Nilsen-Hamilton M. IMAGEtags: Quantifying mRNA Transcription in Real Time with Multiaptamer Reporters. Methods Enzymol 2016; 572:193-213. [PMID: 27241755 DOI: 10.1016/bs.mie.2016.02.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cell communications are essential to the organization, development, and maintenance of multicellular organisms. Much of this communication involves changes in RNA transcription and is dynamic. Most methods for studying transcription require interrupting the continuity of cellular function by sacrificing the communicating cells and capturing gene expression information by periodic sampling of individual cells or the population. The IMAGEtag technology to quantify RNA levels in living cells, demonstrated here in yeast, allows individual cells to be tracked over time as they respond to different environmental cues. IMAGEtags are short RNAs consisting of strings of a variable number of tandem aptamers that bind small-molecule ligands. The aptamer strings can vary in length and in configuration of aptamer constituents, such as to contain multiples of the same aptamer or two or more different aptamers that alternate in their occurrence. A minimum effective length is about five aptamers. The maximum length is undefined. The small-molecule ligands are enabled for imaging as fluorophore conjugates. For each IMAGEtag, two fluorophore conjugates are provided, which are FRET pairs. When a cell expresses an RNA containing an IMAGEtag sequence, the aptamers bind their ligands and bring the fluorophores into sufficiently close proximity to allow FRET. The background fluorescence of both fluorophores is minimal in the FRET channel. These features endow IMAGEtags with the sensitivity to report on mRNA expression levels in living cells.
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Affiliation(s)
- J Ray
- Cornell University, Ithaca, NY, United States.
| | - I Shin
- National Forensic Service, Seoul, South Korea
| | - M Ilgu
- Aptalogic Inc., Ames, IA, United States
| | - L Bendickson
- Ames Laboratory, US DOE, Ames, IA, United States; Iowa State University, Ames, IA, United States
| | - V Gupta
- The Scripps Research Institute, Jupiter, FL, United States
| | - G A Kraus
- Ames Laboratory, US DOE, Ames, IA, United States; Iowa State University, Ames, IA, United States
| | - M Nilsen-Hamilton
- Ames Laboratory, US DOE, Ames, IA, United States; Iowa State University, Ames, IA, United States; Aptalogic Inc., Ames, IA, United States.
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23
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Abstract
Nucleic acid aptamers are promising alternatives to antibodies in analytics. They are generally obtained through an iterative SELEX protocol that enriches a population of synthetic oligonucleotides to a subset that can recognize the chosen target molecule specifically and avidly. A wide range of targets is recognized by aptamers. Once identified and optimized for performance, aptamers can be reproducibly synthesized and offer other key features, like small size, low cost, sensitivity, specificity, rapid response, stability, and reusability. This makes them excellent options for sensory units in a variety of analytical platforms including those with electrochemical, optical, and mass sensitive transduction detection. Many novel sensing strategies have been developed by rational design to take advantage of the tendency of aptamers to undergo conformational changes upon target/analyte binding and employing the principles of base complementarity that can drive the nucleic acid structure. Despite their many advantages over antibodies, surprisingly few aptamers have yet been integrated into commercially available analytical devices. In this review, we discuss how to select and engineer aptamers for their identified application(s), some of the challenges faced in developing aptamers for analytics and many examples of their reported successful performance as sensors in a variety of analytical platforms.
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Affiliation(s)
- Muslum Ilgu
- Roy J Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames IA 50011, USA. and Aptalogic Inc., Ames IA 50014, USA
| | - Marit Nilsen-Hamilton
- Roy J Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames IA 50011, USA. and Aptalogic Inc., Ames IA 50014, USA and Ames Laboratory, US DOE, Ames IA 50011, USA
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24
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Ferraro T, Lucas T, Clémot M, De Las Heras Chanes J, Desponds J, Coppey M, Walczak AM, Dostatni N. New methods to image transcription in living fly embryos: the insights so far, and the prospects. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 5:296-310. [PMID: 26894441 PMCID: PMC5021148 DOI: 10.1002/wdev.221] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/28/2015] [Accepted: 10/30/2015] [Indexed: 11/08/2022]
Abstract
The regulation of transcription is a fundamental process underlying the determination of cell identity and its maintenance during development. In the last decades, most of the transcription factors, which have to be expressed at the right place and at the right time for the proper development of the fly embryo, have been identified. However, mostly because of the lack of methods to visualize transcription as the embryo develops, their coordinated spatiotemporal dynamics remains largely unexplored. Efforts have been made to decipher the transcription process with single molecule resolution at the single cell level. Recently, the fluorescent labeling of nascent RNA in developing fly embryos allowed the direct visualization of ongoing transcription at single loci within each nucleus. Together with powerful imaging and quantitative data analysis, these new methods provide unprecedented insights into the temporal dynamics of the transcription process and its intrinsic noise. Focusing on the Drosophila embryo, we discuss how the detection of single RNA molecules enhanced our comprehension of the transcription process and we outline the potential next steps made possible by these new imaging tools. In combination with genetics and theoretical analysis, these new imaging methods will aid the search for the mechanisms responsible for the robustness of development. For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Teresa Ferraro
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France.,Ecole Normale Superieure, PSL Research University, Paris, France
| | - Tanguy Lucas
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France
| | - Marie Clémot
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France
| | - Jose De Las Heras Chanes
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France
| | - Jonathan Desponds
- UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France.,Ecole Normale Superieure, PSL Research University, Paris, France
| | - Mathieu Coppey
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France
| | - Aleksandra M Walczak
- UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France.,Ecole Normale Superieure, PSL Research University, Paris, France
| | - Nathalie Dostatni
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France
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25
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Xu J, Carrocci TJ, Hoskins AA. Evolution and characterization of a benzylguanine-binding RNA aptamer. Chem Commun (Camb) 2016; 52:549-52. [PMID: 26538152 PMCID: PMC5020705 DOI: 10.1039/c5cc07605f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Repurposing the "protein-labeling toolkit" for RNA research could be a pragmatic approach for developing new RNA-labeling methods. We have evolved an RNA aptamer that tightly binds benzylguanine (bG), the key ligand for the protein SNAP-tag. The aptamer tightly binds bG fluorophores and can be purified from cellular RNA with bG agarose under native conditions.
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Affiliation(s)
- J Xu
- Department of Biochemistry, U. Wisconsin-Madison, 433 Babcock Dr., Madison, WI 53706, USA.
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26
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Abstract
Visualization of single RNA molecules in living cells has enabled the study of synthesis, movement, and localization of mRNAs and has provided insight into gene regulation with sub-second temporal resolution and nanometer spatial resolution. Following transcription in single cells indicates that gene activity is heterogeneous between cells and also exhibits random variability over time even within single cells. Studies of mRNAs in yeast can take advantage of the powerful genetics available in this model organism and allow mechanistic questions to be addressed. In this chapter, we describe an approach for visualizing mRNA and transcription in live yeast cells. The method is based on binding of fluorescently labeled MS2 and PP7 coat proteins to stem loops sequences that are introduced into the gene of interest. We give detailed protocols for the construction of the necessary yeast strains, for image acquisition, and for validation.
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Affiliation(s)
- Tineke L Lenstra
- Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland
| | - Daniel R Larson
- Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland
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27
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Ilgu M, Ray J, Bendickson L, Wang T, Geraskin IM, Kraus GA, Nilsen-Hamilton M. Light-up and FRET aptamer reporters; evaluating their applications for imaging transcription in eukaryotic cells. Methods 2015; 98:26-33. [PMID: 26707205 DOI: 10.1016/j.ymeth.2015.12.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/11/2015] [Accepted: 12/15/2015] [Indexed: 11/19/2022] Open
Abstract
The regulation of RNA transcription is central to cellular function. Changes in gene expression drive differentiation and cellular responses to events such as injury. RNA trafficking can also have a large impact on protein expression and its localization. Thus, the ability to image RNA transcription and trafficking in real time and in living cells is a worthwhile goal that has been difficult to achieve. The availability of "light-up" aptamers that cause an increase in fluorescence of their ligands when bound by the aptamer have shown promise for reporting on RNA production and localization in vivo. Here we have investigated two light-up aptamers (the malachite green aptamer and the Spinach aptamers) for their suitabilities as reporters of RNA expression in vivo using two eukaryotic cell types, yeast and mammalian. Our analysis focused on the aptamer ligands, their contributions to background noise, and the impact of tandem aptamer strings on signal strength and ligand affinity. Whereas the background fluorescence is very low in vitro, this is not always true for cell imaging. Our results suggest the need for caution in using light-up aptamers as reporters for imaging RNA. In particular, images should be collected and analyzed by operators blinded to the sample identities. The appropriate control condition of ligand with the cells in the absence of aptamer expression must be included in each experiment. This control condition establishes that the specific interaction of ligand with aptamer, rather than nonspecific interactions with unknown cell elements, is responsible for the observed fluorescent signals. High background signals due to nonspecific interactions of aptamer ligands with cell components can be minimized by using IMAGEtags (Intracellular Multiaptamer GEnetic tags), which signal by FRET and are promising RNA reporters for imaging transcription.
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Affiliation(s)
- Muslum Ilgu
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, United States
| | - Judhajeet Ray
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, United States
| | - Lee Bendickson
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, United States; Ames Laboratory, US DOE, United States
| | | | | | - George A Kraus
- Department of Chemistry, Ames, IA, United States; Ames Laboratory, US DOE, United States
| | - Marit Nilsen-Hamilton
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, United States; Ames Laboratory, US DOE, United States.
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28
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Zhang J, Fei J, Leslie BJ, Han KY, Kuhlman TE, Ha T. Tandem Spinach Array for mRNA Imaging in Living Bacterial Cells. Sci Rep 2015; 5:17295. [PMID: 26612428 PMCID: PMC4661537 DOI: 10.1038/srep17295] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/15/2015] [Indexed: 12/24/2022] Open
Abstract
Live cell RNA imaging using genetically encoded fluorescent labels is an important tool for monitoring RNA activities. A recently reported RNA aptamer-fluorogen system, the Spinach, in which an RNA aptamer binds and induces the fluorescence of a GFP-like 3,5-difluoro-4-hydroxybenzylidene imidazolinone (DFHBI) ligand, can be readily tagged to the RNA of interest. Although the aptamer-fluorogen system is sufficient for imaging highly abundant non-coding RNAs (tRNAs, rRNAs, etc.), it performs poorly for mRNA imaging due to low brightness. In addition, whether the aptamer-fluorogen system may perturb the native RNA characteristics has not been systematically characterized at the levels of RNA transcription, translation and degradation. To increase the brightness of these aptamer-fluorogen systems, we constructed and tested tandem arrays containing multiple Spinach aptamers (8-64 aptamer repeats). Such arrays enhanced the brightness of the tagged mRNA molecules by up to ~17 fold in living cells. Strong laser excitation with pulsed illumination further increased the imaging sensitivity of Spinach array-tagged RNAs. Moreover, transcriptional fusion to the Spinach array did not affect mRNA transcription, translation or degradation, indicating that aptamer arrays might be a generalizable labeling method for high-performance and low-perturbation live cell RNA imaging.
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Affiliation(s)
- Jichuan Zhang
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Jingyi Fei
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Benjamin J. Leslie
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- Howard Hughes Medical Institute, Baltimore, MD 21205 USA
| | - Kyu Young Han
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- Howard Hughes Medical Institute, Baltimore, MD 21205 USA
| | - Thomas E. Kuhlman
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Taekjip Ha
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218 USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205 USA
- Howard Hughes Medical Institute, Baltimore, MD 21205 USA
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29
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Oscope identifies oscillatory genes in unsynchronized single-cell RNA-seq experiments. Nat Methods 2015; 12:947-950. [PMID: 26301841 PMCID: PMC4589503 DOI: 10.1038/nmeth.3549] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 06/05/2015] [Indexed: 01/24/2023]
Abstract
Oscillatory gene expression is fundamental to mammalian development, but technologies to monitor expression oscillations are limited. We have developed a statistical approach called Oscope to identify and characterize the transcriptional dynamics of oscillating genes in single-cell RNA-seq data from an unsynchronized cell population. Applications to a number of data sets demonstrate the utility of the approach and also identify a potential artifact in the Fluidigm C1 platform.
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30
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Walker CL, Lukyanov KA, Yampolsky IV, Mishin AS, Bommarius AS, Duraj-Thatte AM, Azizi B, Tolbert LM, Solntsev KM. Fluorescence imaging using synthetic GFP chromophores. Curr Opin Chem Biol 2015; 27:64-74. [DOI: 10.1016/j.cbpa.2015.06.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 05/21/2015] [Accepted: 06/05/2015] [Indexed: 01/22/2023]
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31
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Arora A, Sunbul M, Jäschke A. Dual-colour imaging of RNAs using quencher- and fluorophore-binding aptamers. Nucleic Acids Res 2015; 43:e144. [PMID: 26175046 PMCID: PMC4666381 DOI: 10.1093/nar/gkv718] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 07/02/2015] [Indexed: 01/12/2023] Open
Abstract
In order to gain deeper insight into the functions and dynamics of RNA in cells, the development of methods for imaging multiple RNAs simultaneously is of paramount importance. Here, we describe a modular approach to image RNA in living cells using an RNA aptamer that binds to dinitroaniline, an efficient general contact quencher. Dinitroaniline quenches the fluorescence of different fluorophores when directly conjugated to them via ethylene glycol linkers by forming a non-fluorescent intramolecular complex. Since the binding of the RNA aptamer to the quencher destroys the fluorophore-quencher complex, fluorescence increases dramatically upon binding. Using this principle, a series of fluorophores were turned into fluorescent turn-on probes by conjugating them to dinitroaniline. These probes ranged from fluorescein-dinitroaniline (green) to TexasRed-dinitroaniline (red) spanning across the visible spectrum. The dinitroaniline-binding aptamer (DNB) was generated by in vitro selection, and was found to bind all probes, leading to fluorescence increase in vitro and in living cells. When expressed in E. coli, the DNB aptamer could be labelled and visualized with different-coloured fluorophores and therefore it can be used as a genetically encoded tag to image target RNAs. Furthermore, combining contact-quenched fluorogenic probes with orthogonal DNB (the quencher-binding RNA aptamer) and SRB-2 aptamers (a fluorophore-binding RNA aptamer) allowed dual-colour imaging of two different fluorescence-enhancing RNA tags in living cells, opening new avenues for studying RNA co-localization and trafficking.
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Affiliation(s)
- Ankita Arora
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, Heidelberg 69120, Germany
| | - Murat Sunbul
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, Heidelberg 69120, Germany
| | - Andres Jäschke
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, Heidelberg 69120, Germany
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32
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Nelles DA, Fang MY, Aigner S, Yeo GW. Applications of Cas9 as an RNA-programmed RNA-binding protein. Bioessays 2015; 37:732-9. [PMID: 25880497 DOI: 10.1002/bies.201500001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The Streptococcus pyogenes CRISPR-Cas system has gained widespread application as a genome editing and gene regulation tool as simultaneous cellular delivery of the Cas9 protein and guide RNAs enables recognition of specific DNA sequences. The recent discovery that Cas9 can also bind and cleave RNA in an RNA-programmable manner indicates the potential utility of this system as a universal nucleic acid-recognition technology. RNA-targeted Cas9 (RCas9) could allow identification and manipulation of RNA substrates in live cells, empowering the study of cellular gene expression, and could ultimately spawn patient- and disease-specific diagnostic and therapeutic tools. Here we describe the development of RCas9 and compare it to previous methods for RNA targeting, including engineered RNA-binding proteins and other types of CRISPR-Cas systems. We discuss potential uses ranging from live imaging of transcriptional dynamics to patient-specific therapies and applications in synthetic biology.
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Affiliation(s)
- David A Nelles
- Department of Cellular and Molecular Medicine, Stem Cell Program, and Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Mark Y Fang
- Department of Cellular and Molecular Medicine, Stem Cell Program, and Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Stefan Aigner
- Department of Cellular and Molecular Medicine, Stem Cell Program, and Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, Stem Cell Program, and Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA.,Molecular Engineering Laboratory, Biomedical Sciences Institutes, Agency for Science, Technology & Research and Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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33
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Genetically encoded tools for RNA imaging in living cells. Curr Opin Biotechnol 2015; 31:42-9. [DOI: 10.1016/j.copbio.2014.07.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 07/30/2014] [Indexed: 12/11/2022]
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Spille JH, Kubitscheck U. Labelling and imaging of single endogenous messenger RNA particles in vivo. J Cell Sci 2015; 128:3695-706. [DOI: 10.1242/jcs.166728] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
ABSTRACT
RNA molecules carry out widely diverse functions in numerous different physiological processes in living cells. The RNA life cycle from transcription, through the processing of nascent RNA, to the regulatory function of non-coding RNA and cytoplasmic translation of messenger RNA has been studied extensively using biochemical and molecular biology techniques. In this Commentary, we highlight how single molecule imaging and particle tracking can yield further insight into the dynamics of RNA particles in living cells. In the past few years, a variety of bright and photo-stable labelling techniques have been developed to generate sufficient contrast for imaging of single endogenous RNAs in vivo. New imaging modalities allow determination of not only lateral but also axial positions with high precision within the cellular context, and across a wide range of specimen from yeast and bacteria to cultured cells, and even multicellular organisms or live animals. A whole range of methods to locate and track single particles, and to analyze trajectory data are available to yield detailed information about the kinetics of all parts of the RNA life cycle. Although the concepts presented are applicable to all types of RNA, we showcase here the wealth of information gained from in vivo imaging of single particles by discussing studies investigating dynamics of intranuclear trafficking, nuclear pore transport and cytoplasmic transport of endogenous messenger RNA.
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Affiliation(s)
- Jan-Hendrik Spille
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-University Bonn, Wegeler Str. 12, Bonn 53115, Germany
| | - Ulrich Kubitscheck
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-University Bonn, Wegeler Str. 12, Bonn 53115, Germany
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Sabherwal P, Shorie M, Pathania P, Chaudhary S, Bhasin KK, Bhalla V, Suri CR. Hybrid aptamer-antibody linked fluorescence resonance energy transfer based detection of trinitrotoluene. Anal Chem 2014; 86:7200-4. [PMID: 25008849 DOI: 10.1021/ac501388a] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Combining synthetic macromolecules and biomolecular recognition units are promising in developing novel diagnostic and analysis techniques for detecting environmental and/or clinically important substances. Fluorescence resonance energy transfer (FRET) apta-immunosensor for explosive detection is reported using 2,4,6-trinitrotoluene (TNT) specific aptamer and antibodies tagged with respective FRET pair dyes in a sandwich immunoassay format. FITC-labeled aptamer was used as a binder molecule in the newly developed apta-immunoassay format where the recognition element was specific anti-TNT antibody labeled with rhodamine isothiocyanate. The newly developed sensing platform showed excellent sensitivity with a detection limit of the order of 0.4 nM presenting a promising candidate for routine screening of TNT in samples.
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Affiliation(s)
- Priyanka Sabherwal
- Institute of Nano Science and Technology , Sector 64, Mohali 160064, India
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