1
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Vallina NS, McRae EKS, Geary C, Andersen ES. An RNA origami robot that traps and releases a fluorescent aptamer. SCIENCE ADVANCES 2024; 10:eadk1250. [PMID: 38507482 PMCID: PMC10954211 DOI: 10.1126/sciadv.adk1250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 02/15/2024] [Indexed: 03/22/2024]
Abstract
RNA nanotechnology aims to use RNA as a programmable material to create self-assembling nanodevices for application in medicine and synthetic biology. The main challenge is to develop advanced RNA robotic devices that both sense, compute, and actuate to obtain enhanced control over molecular processes. Here, we use the RNA origami method to prototype an RNA robotic device, named the "Traptamer," that mechanically traps the fluorescent aptamer, iSpinach. The Traptamer is shown to sense two RNA key strands, acts as a Boolean AND gate, and reversibly controls the fluorescence of the iSpinach aptamer. Cryo-electron microscopy of the closed Traptamer structure at 5.45-angstrom resolution reveals the mechanical mode of distortion of the iSpinach motif. Our study suggests a general approach to distorting RNA motifs and a path forward to build sophisticated RNA machines that through sensing, computing, and actuation modules can be used to precisely control RNA functionalities in cellular systems.
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Affiliation(s)
| | - Ewan K. S. McRae
- Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark
- Center for RNA Therapeutics, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave, R10-117, Houston, TX 77030, USA
| | - Cody Geary
- Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark
| | - Ebbe S. Andersen
- Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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2
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Abdolahzadeh A, Ang QR, Caine JR, Panchapakesan SSS, Thio S, Cojocaru R, Unrau PJ. Turn-on RNA Mango Beacons for trans-acting fluorogenic nucleic acid detection. RNA (NEW YORK, N.Y.) 2024; 30:392-403. [PMID: 38282417 PMCID: PMC10946430 DOI: 10.1261/rna.079833.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 01/03/2024] [Indexed: 01/30/2024]
Abstract
The Mango I and II RNA aptamers have been widely used in vivo and in vitro as genetically encodable fluorogenic markers that undergo large increases in fluorescence upon binding to their ligand, TO1-Biotin. However, while studying nucleic acid sequences, it is often desirable to have trans-acting probes that induce fluorescence upon binding to a target sequence. Here, we rationally design three types of light-up RNA Mango Beacons based on a minimized Mango core that induces fluorescence upon binding to a target RNA strand. Our first design is bimolecular in nature and uses a DNA inhibition strand to prevent folding of the Mango aptamer core until binding to a target RNA. Our second design is unimolecular in nature, and features hybridization arms flanking the core that inhibit G-quadruplex folding until refolding is triggered by binding to a target RNA strand. Our third design builds upon this structure, and incorporates a self-inhibiting domain into one of the flanking arms that deliberately binds to, and precludes folding of, the aptamer core until a target is bound. This design separates G-quadruplex folding inhibition and RNA target hybridization into separate modules, enabling a more universal unimolecular beacon design. All three Mango Beacons feature high contrasts and low costs when compared to conventional molecular beacons, with excellent potential for in vitro and in vivo applications.
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Affiliation(s)
- Amir Abdolahzadeh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Quiana R Ang
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Jana R Caine
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | | | - Shinta Thio
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Razvan Cojocaru
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Peter J Unrau
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
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3
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Emanuelson C, Bardhan A, Deiters A. DNA Logic Gates for Small Molecule Activation Circuits in Cells. ACS Synth Biol 2024; 13:538-545. [PMID: 38306634 PMCID: PMC10877608 DOI: 10.1021/acssynbio.3c00474] [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: 08/02/2023] [Revised: 01/09/2024] [Accepted: 01/09/2024] [Indexed: 02/04/2024]
Abstract
DNA-based devices such as DNA logic gates self-assemble into supramolecular structures, as dictated by the sequences of the constituent oligonucleotides and their predictable Watson-Crick base pairing interactions. The programmable nature of DNA-based devices permits the design and implementation of DNA circuits that interact in a dynamic and sequential manner capable of spatially arranging disparate DNA species. Here, we report the application of an activatable fluorescence reporter based on a proximity-driven inverse electron demand Diels-Alder (IEDDA) reaction and its robust integration with DNA strand displacement circuits. In response to specific DNA input patterns, sequential strand displacement reactions are initiated and culminate in the hybridization of two modified DNA strands carrying probes capable of undergoing an IEDDA reaction between a vinyl-ether-caged fluorophore and its reactive partner tetrazine, leading to the activation of fluorescence. This approach provides a major advantage for DNA computing in mammalian cells since circuit degradation does not induce fluorescence, in contrast to traditional fluorophore-quencher designs. We demonstrate the robustness and sensitivity of the reporter by testing its ability to serve as a readout for DNA logic circuits of varying complexity inside cells.
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Affiliation(s)
- Cole Emanuelson
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Anirban Bardhan
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Alexander Deiters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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4
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Tang AA, Afasizheva A, Cano CT, Plath K, Black D, Franco E. Optimization of RNA Pepper Sensors for the Detection of Arbitrary RNA Targets. ACS Synth Biol 2024; 13:498-508. [PMID: 38295291 DOI: 10.1021/acssynbio.3c00426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
The development of fluorescent light-up RNA aptamers (FLAPs) has paved the way for the creation of sensors to track RNA in live cells. A major challenge with FLAP sensors is their brightness and limited signal-to-background ratio both in vivo and in vitro. To address this, we develop sensors using the Pepper aptamer, which exhibits superior brightness and photostability when compared to other FLAPs. The sensors are designed to fold into a low fluorescence conformation and to switch to a high fluorescence conformation through toehold or loop-mediated interactions with their RNA target. Our sensors detect RNA targets as short as 20 nucleotides in length with a wide dynamic range over 300-fold in vitro, and we describe strategies for optimizing the sensor's performance for any given RNA target. To demonstrate the versatility of our design approach, we generated Pepper sensors for a range of specific, biologically relevant RNA sequences. Our design and optimization strategies are portable to other FLAPs and offer a promising foundation for future development of RNA sensors with high specificity and sensitivity for detecting RNA biomarkers with multiple applications.
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Affiliation(s)
- Anli A Tang
- Department of Mechanical and Aerospace Engineering, University of California at Los Angeles, Los Angeles, California 90095, United States
| | - Anna Afasizheva
- Department of Biological Chemistry, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California 90095, United States
| | - Clara T Cano
- Department of Biological Chemistry, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California 90095, United States
| | - Kathrin Plath
- Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095, United States
- Department of Biological Chemistry, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California 90095, United States
- Jonsson Comprehensive Cancer Center, Brain Research Institute, Graduate Program in the Biosciences, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Douglas Black
- Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095, United States
- Jonsson Comprehensive Cancer Center, Brain Research Institute, Graduate Program in the Biosciences, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, California 90095, United States
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Elisa Franco
- Department of Mechanical and Aerospace Engineering, University of California at Los Angeles, Los Angeles, California 90095, United States
- Department of Bioengineering, University of California at Los Angeles, Los Angeles, California 90095, United States
- Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095, United States
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5
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Wang T, Simmel FC. Switchable Fluorescent Light-Up Aptamers Based on Riboswitch Architectures. Angew Chem Int Ed Engl 2023; 62:e202302858. [PMID: 37163453 DOI: 10.1002/anie.202302858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/08/2023] [Accepted: 05/10/2023] [Indexed: 05/12/2023]
Abstract
Fluorescent light-up RNA aptamers (FLAPs) such as Spinach or Mango can bind small fluorogens and activate their fluorescence. Here, we adopt a switching mechanism otherwise found in riboswitches and use it to engineer switchable FLAPs that can be activated or repressed by trigger oligonucleotides or small metabolites. The fluorophore binding pocket of the FLAPs comprises guanine (G) quadruplexes, whose critical nucleotides can be sequestered by corresponding anti-FLAP sequences, leading to an inactive conformation and thus preventing association with the fluorophore. We modified the FLAPs with designed toehold hairpins that carry either an anti-FLAP or an anti-anti-FLAP sequence within the loop region. The addition of an input RNA molecule triggers a toehold-mediated strand invasion process that refolds the FLAP into an active or inactive configuration. Several of our designs display close-to-zero leak signals and correspondingly high ON/OFF fluorescence ratios. We also modified purine aptamers to sequester a partial anti-FLAP or an anti-anti-FLAP sequence to control the formation of the fluorogen-binding conformation, resulting in FLAPs whose fluorescence is activated or deactivated in the presence of guanine or adenine. We demonstrate that switching modules can be easily combined to generate FLAPs whose fluorescence depends on several inputs with different types of input logic.
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Affiliation(s)
- Tianhe Wang
- Physics of Synthetic Biological Systems-E14, Department of Bioscience, TUM School of Natural Science, Technische Universität München, Am Coulombwall 4a, 85748, Garching, Germany
| | - Friedrich C Simmel
- Physics of Synthetic Biological Systems-E14, Department of Bioscience, TUM School of Natural Science, Technische Universität München, Am Coulombwall 4a, 85748, Garching, Germany
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6
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Yan Z, Tang AA, Eshed A, Ticktin ZM, Chaudhary S, Ma D, McCutcheon G, Li Y, Wu K, Saha S, Alcantar-Fernandez J, Moreno-Camacho JL, Campos-Romero A, Collins JJ, Yin P, Green AA. Rapid and Multiplexed Nucleic Acid Detection using Programmable Aptamer-Based RNA Switches. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.06.02.23290873. [PMID: 37333364 PMCID: PMC10275000 DOI: 10.1101/2023.06.02.23290873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Rapid, simple, and low-cost diagnostic technologies are crucial tools for combatting infectious disease. Here, we describe a class of aptamer-based RNA switches called aptaswitches that recognize specific target nucleic acid molecules and respond by initiating folding of a reporter aptamer. Aptaswitches can detect virtually any sequence and provide a fast and intense fluorescent readout, generating signals in as little as 5 minutes and enabling detection by eye with minimal equipment. We demonstrate that aptaswitches can be used to regulate folding of six different fluorescent aptamer/fluorogen pairs, providing a general means of controlling aptamer activity and an array of different reporter colors for multiplexing. By coupling isothermal amplification reactions with aptaswitches, we reach sensitivities down to 1 RNA copy/μL in one-pot reactions. Application of multiplexed one-pot reactions against RNA extracted from clinical saliva samples yields an overall accuracy of 96.67% for detection of SARS-CoV-2 in 30 minutes. Aptaswitches are thus versatile tools for nucleic acid detection that can be readily integrated into rapid diagnostic assays.
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Affiliation(s)
- Zhaoqing Yan
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
- Molecular Biology, Cell Biology & Biochemistry Program, Graduate School of Arts and Sciences, Boston University, Boston, MA, USA
- Biological Design Center, Boston University, Boston, MA 02215, USA
- These authors contributed equally: Zhaoqing Yan, Anli A. Tang
| | - Anli A. Tang
- Biodesign Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, USA
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
- These authors contributed equally: Zhaoqing Yan, Anli A. Tang
| | - Amit Eshed
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
- Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Zackary M. Ticktin
- Biodesign Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Soma Chaudhary
- Biodesign Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, USA
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
| | - Duo Ma
- Biodesign Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, USA
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
| | - Griffin McCutcheon
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
- Biological Design Center, Boston University, Boston, MA 02215, USA
- Biodesign Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Yudan Li
- Molecular Biology, Cell Biology & Biochemistry Program, Graduate School of Arts and Sciences, Boston University, Boston, MA, USA
- Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Kaiyue Wu
- Molecular Biology, Cell Biology & Biochemistry Program, Graduate School of Arts and Sciences, Boston University, Boston, MA, USA
- Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Sanchari Saha
- Biodesign Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, USA
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
| | | | | | | | - James J. Collins
- Department of Biological Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Institute for Medical Engineering and Science, MIT, Cambridge, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Peng Yin
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - Alexander A. Green
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
- Molecular Biology, Cell Biology & Biochemistry Program, Graduate School of Arts and Sciences, Boston University, Boston, MA, USA
- Biological Design Center, Boston University, Boston, MA 02215, USA
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
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7
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Multi-arm RNA junctions encoding molecular logic unconstrained by input sequence for versatile cell-free diagnostics. Nat Biomed Eng 2022; 6:298-309. [PMID: 35288660 PMCID: PMC8940621 DOI: 10.1038/s41551-022-00857-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 02/07/2022] [Indexed: 12/12/2022]
Abstract
Applications of RNA-based molecular logic have been hampered by sequence constraints imposed on the input and output of the circuits. Here we show that the sequence constraints can be substantially reduced by appropriately encoded multi-arm junctions of single-stranded RNA structures. To conditionally activate RNA translation, we integrated multi-arm junctions, self-assembled upstream of a regulated gene and designed to unfold sequentially in response to different RNA inputs, with motifs of loop-initiated RNA activators that function independently of the sequence of the input RNAs and that reduce interference with the output gene. We used the integrated RNA system and sequence-independent input RNAs to execute two-input and three-input OR and AND logic in Escherichia coli, and designed paper-based cell-free colourimetric assays that accurately identified two human immunodeficiency virus (HIV) subtypes (by executing OR logic) in amplified synthetic HIV RNA as well as severe acute respiratory syndrome coronavirus-2 (via two-input AND logic) in amplified RNA from saliva samples. The sequence-independent molecular logic enabled by the integration of multi-arm junction RNAs with motifs for loop-initiated RNA activators may be broadly applicable in biotechnology.
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8
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Citartan M. The dynamicity of light-up aptamers in one-pot in vitro diagnostic assays. Analyst 2021; 147:10-21. [PMID: 34860215 DOI: 10.1039/d1an01690c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Light-up aptamers are aptamers that ignite the fluorescence emission of certain dyes upon binding. Widely harnessed in in vivo imaging, the binding capacity of the light-up aptamers can also be deployed in in vitro diagnostic assays, engendering a mix-and-read format. Intrigued by this, I intend to provide an overview of the various formats of diagnostic assays developed using light-up aptamers from the direct modulation of the light-up aptamers, split aptamer-based configuration, strand displacement, in vitro transcription-based one-pot diagnostic assay, CRISPR-Cas system to the measurement of the ion reliance. The incorporation of the light-up aptamers into each configuration is expounded and further supported by describing the exemplary assays developed thus far. It is anticipated that the present study can be enlightening to any researchers who aspire to embark on the development of one-pot in vitro diagnostic assays based on light-up aptamers.
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Affiliation(s)
- Marimuthu Citartan
- Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia, Bertam, 13200, Kepala Batas, Penang, Malaysia.
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9
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Oliveira-Jr GP, Barbosa RH, Thompson L, Pinckney B, Murphy-Thornley M, Lu S, Jones J, Hansen CH, Tigges J, Wong WP, Ghiran IC. Electrophoretic mobility shift as a molecular beacon-based readout for miRNA detection. Biosens Bioelectron 2021; 189:113307. [PMID: 34062334 PMCID: PMC8461749 DOI: 10.1016/j.bios.2021.113307] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/27/2021] [Accepted: 05/03/2021] [Indexed: 12/24/2022]
Abstract
MicroRNAs are short, non-coding RNA sequences involved in gene expression regulation. Quantification of miRNAs in biological fluids involves time consuming and laborious methods such as Northern blotting or PCR-based techniques. Molecular beacons (MB) are an attractive means for rapid detection of miRNAs, although the need for sophisticated readout methods limits their use in research and clinical settings. Here, we introduce a novel method based on delayed electrophoretic mobility, as a quantitative means for detection of miRNAs-MB hybridization. Upon hybridization with the target miRNAs, MB form a fluorescent duplex with reduced electrophoretic mobility, thus bypassing the need for additional staining. In addition to emission of light, the location of the fluorescent band on the gel acts as an orthogonal validation of the target identity, further confirming the specificity of binding. The limit of detection of this approach is approximately 100 pM, depending on the MB sequence. The method is sensitive enough to detect specific red blood cell miRNAs molecules in total RNA, with single nucleotide specificity. Altogether, we describe a rapid and affordable method that offers sensitive detection of single-stranded small DNA and RNA sequences.
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Affiliation(s)
- Getulio P Oliveira-Jr
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States.
| | - Raquel H Barbosa
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Lauren Thompson
- Nano Flow Core Facility, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Brandy Pinckney
- Nano Flow Core Facility, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Moriah Murphy-Thornley
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Shulin Lu
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Jennifer Jones
- Laboratory of Pathology Center for Cancer Research, National Cancer Institute, Bethesda, MD, United States
| | - Clinton H Hansen
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
| | - John Tigges
- Nano Flow Core Facility, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Wesley P Wong
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
| | - Ionita C Ghiran
- Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States.
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10
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Ryckelynck M. Development and Applications of Fluorogen/Light-Up RNA Aptamer Pairs for RNA Detection and More. Methods Mol Biol 2021; 2166:73-102. [PMID: 32710404 DOI: 10.1007/978-1-0716-0712-1_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The central role of RNA in living systems made it highly desirable to have noninvasive and sensitive technologies allowing for imaging the synthesis and the location of these molecules in living cells. This need motivated the development of small pro-fluorescent molecules called "fluorogens" that become fluorescent upon binding to genetically encodable RNAs called "light-up aptamers." Yet, the development of these fluorogen/light-up RNA pairs is a long and thorough process starting with the careful design of the fluorogen and pursued by the selection of a specific and efficient synthetic aptamer. This chapter summarizes the main design and the selection strategies used up to now prior to introducing the main pairs. Then, the vast application potential of these molecules for live-cell RNA imaging and other applications is presented and discussed.
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Affiliation(s)
- Michael Ryckelynck
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, Strasbourg, France.
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11
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Kolpashchikov DM, Spelkov AA. Binary (Split) Light‐up Aptameric Sensors. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.201914919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Dmitry M. Kolpashchikov
- Chemistry Department University of Central Florida Orlando FL 32816-2366 USA
- Burnett School of Biomedical Sciences University of Central Florida Orlando FL 32816 USA
| | - Alexander A. Spelkov
- Laboratory of Solution Chemistry of Advanced Materials and Technologies ITMO University 9 Lomonosova Str. St. Petersburg 191002 Russian Federation
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12
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Khan P, Aufdembrink LM, Engelhart AE. Isothermal SARS-CoV-2 Diagnostics: Tools for Enabling Distributed Pandemic Testing as a Means of Supporting Safe Reopenings. ACS Synth Biol 2020; 9:2861-2880. [PMID: 32966744 PMCID: PMC7552996 DOI: 10.1021/acssynbio.0c00359] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Indexed: 02/06/2023]
Abstract
The COVID-19 pandemic, caused by the SARS-CoV-2 virus, poses grave threats to both the global economy and health. The predominant diagnostic screens in use for SARS-CoV-2 detection are molecular techniques such as nucleic acid amplification tests. In this Review, we compare current and emerging isothermal diagnostic methods for COVID-19. We outline the molecular and serological techniques currently being used to detect SARS-CoV-2 infection, past or present, in patients. We also discuss ongoing research on isothermal techniques, CRISPR-mediated detection assays, and point-of-care diagnostics that have potential for use in SARS-CoV-2 detection. Large-scale viral testing during a global pandemic presents unique challenges, chief among them the simultaneous need for testing supplies, durable equipment, and personnel in many regions worldwide, with each of these regions possessing testing needs that vary as the pandemic progresses. The low-cost isothermal technologies described in this Review provide a promising means by which to address these needs and meet the global need for testing of symptomatic individuals as well as provide a possible means for routine testing of asymptomatic individuals, providing a potential means of safely enabling reopenings and early monitoring of outbreaks.
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Affiliation(s)
- Pavana Khan
- Department of Genetics, Cell Biology, and Development,
University of Minnesota, 6-160 Jackson Hall, 321 Church
Street SE, Minneapolis, Minnesota 55455, United States
| | - Lauren M. Aufdembrink
- Department of Genetics, Cell Biology, and Development,
University of Minnesota, 6-160 Jackson Hall, 321 Church
Street SE, Minneapolis, Minnesota 55455, United States
| | - Aaron E. Engelhart
- Department of Genetics, Cell Biology, and Development,
University of Minnesota, 6-160 Jackson Hall, 321 Church
Street SE, Minneapolis, Minnesota 55455, United States
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13
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Kolpashchikov DM, Spelkov AA. Binary (Split) Light-up Aptameric Sensors. Angew Chem Int Ed Engl 2020; 60:4988-4999. [PMID: 32208549 DOI: 10.1002/anie.201914919] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Indexed: 12/12/2022]
Abstract
This Minireview discusses the design and applications of binary (also known as split) light-up aptameric sensors (BLAS). BLAS consist of two RNA or DNA strands and a fluorogenic organic dye added as a buffer component. When associated, the two strands form a dye-binding site, followed by an increase in fluorescence of the aptamer-bound dye. The design is cost-efficient because it uses short oligonucleotides and does not require conjugation of organic dyes with nucleic acids. In some applications, BLAS design is preferable over monolithic sensors because of simpler assay optimization and improved selectivity. RNA-based BLAS can be expressed in cells and used for the intracellular monitoring of biological molecules. BLAS have been used as reporters of nucleic acid association events in RNA nanotechnology and nucleic-acid-based molecular computation. Other applications of BLAS include the detection of nucleic acids, proteins, and cancer cells, and potentially they can be tailored to report a broad range of biological analytes.
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Affiliation(s)
- Dmitry M Kolpashchikov
- Chemistry Department, University of Central Florida, Orlando, FL, 32816-2366, USA.,Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32816, USA
| | - Alexander A Spelkov
- Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, 9 Lomonosova Str., St. Petersburg, 191002, Russian Federation
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14
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Abstract
In recent years, a diverse set of mechanisms have been developed that allow DNA strands with specific sequences to sense information in their environment and to control material assembly, disassembly, and reconfiguration. These sequences could serve as the inputs and outputs for DNA computing circuits, enabling DNA circuits to act as chemical information processors to program complex behavior in chemical and material systems. This review describes processes that can be sensed and controlled within such a paradigm. Specifically, there are interfaces that can release strands of DNA in response to chemical signals, wavelengths of light, pH, or electrical signals, as well as DNA strands that can direct the self-assembly and dynamic reconfiguration of DNA nanostructures, regulate particle assemblies, control encapsulation, and manipulate materials including DNA crystals, hydrogels, and vesicles. These interfaces have the potential to enable chemical circuits to exert algorithmic control over responsive materials, which may ultimately lead to the development of materials that grow, heal, and interact dynamically with their environments.
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Affiliation(s)
- Dominic Scalise
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Rebecca Schulman
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.,Department of Computer Science, Johns Hopkins University, Baltimore, Maryland 21218, USA;
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15
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Debiais M, Lelievre A, Smietana M, Müller S. Splitting aptamers and nucleic acid enzymes for the development of advanced biosensors. Nucleic Acids Res 2020; 48:3400-3422. [PMID: 32112111 PMCID: PMC7144939 DOI: 10.1093/nar/gkaa132] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/12/2020] [Accepted: 02/18/2020] [Indexed: 12/16/2022] Open
Abstract
In analogy to split-protein systems, which rely on the appropriate fragmentation of protein domains, split aptamers made of two or more short nucleic acid strands have emerged as novel tools in biosensor set-ups. The concept relies on dissecting an aptamer into a series of two or more independent fragments, able to assemble in the presence of a specific target. The stability of the assembled structure can further be enhanced by functionalities that upon folding would lead to covalent end-joining of the fragments. To date, only a few aptamers have been split successfully, and application of split aptamers in biosensing approaches remains as promising as it is challenging. Further improving the stability of split aptamer target complexes and with that the sensitivity as well as efficient working modes are important tasks. Here we review functional nucleic acid assemblies that are derived from aptamers and ribozymes/DNAzymes. We focus on the thrombin, the adenosine/ATP and the cocaine split aptamers as the three most studied DNA split systems and on split DNAzyme assemblies. Furthermore, we extend the subject into split light up RNA aptamers used as mimics of the green fluorescent protein (GFP), and split ribozymes.
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Affiliation(s)
- Mégane Debiais
- Institut des Biomolécules Max Mousseron, University of Montpellier, CNRS, ENCSM, Montpellier, France
| | - Amandine Lelievre
- University Greifswald, Institute for Biochemistry, Greifswald, Germany
| | - Michael Smietana
- Institut des Biomolécules Max Mousseron, University of Montpellier, CNRS, ENCSM, Montpellier, France
| | - Sabine Müller
- University Greifswald, Institute for Biochemistry, Greifswald, Germany
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16
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Kobori S, Nomura Y, Yokobayashi Y. Self-powered RNA nanomachine driven by metastable structure. Nucleic Acids Res 2019; 47:6007-6014. [PMID: 31076769 PMCID: PMC6582335 DOI: 10.1093/nar/gkz364] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/25/2019] [Accepted: 04/29/2019] [Indexed: 11/14/2022] Open
Abstract
Many non-coding and regulatory RNA elements have evolved to exploit transient or metastable structures that emerge during transcription to control complex folding pathways or to encode dynamic functions. However, efforts to engineer synthetic RNA devices have mostly focused on the thermodynamically stable structures. Consequently, significant challenges and opportunities exist in engineering functional RNAs that explicitly take advantage of cotranscriptionally generated transient or metastable structures. In this work, we designed a short RNA sequence that adopts a robust metastable structure when transcribed by an RNA polymerase. Although the metastable structure persists for hours at low temperature, it refolds almost completely into the thermodynamically stable structure upon heat denaturation followed by cooling. The synthetic RNA was also equipped with the Broccoli aptamer so that it can bind its ligand and become fluorescent only in the thermodynamically stable structure. We further demonstrated that the relaxation to the thermodynamically stable and fluorescent structure can be catalyzed by a short trigger RNA in a sequence-specific manner. Finally, the RNA architecture was redesigned to sense and respond to microRNA sequences. In summary, we designed RNA nanomachines that can detect an RNA sequence, amplify signal and produce an optical output, all encoded in a single RNA transcript, self-powered by a metastable structure.
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Affiliation(s)
- Shungo Kobori
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904 0495, Japan
| | - Yoko Nomura
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904 0495, Japan
| | - Yohei Yokobayashi
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904 0495, Japan
- To whom correspondence should be addressed. Tel: +81 989 823 396; Fax: +81 989 823 421;
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17
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Zhou L, Kim SC, Ho KH, O'Flaherty DK, Giurgiu C, Wright TH, Szostak JW. Non-enzymatic primer extension with strand displacement. eLife 2019; 8:e51888. [PMID: 31702557 PMCID: PMC6872209 DOI: 10.7554/elife.51888] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 11/07/2019] [Indexed: 12/20/2022] Open
Abstract
Non-enzymatic RNA self-replication is integral to the emergence of the 'RNA World'. Despite considerable progress in non-enzymatic template copying, demonstrating a full replication cycle remains challenging due to the difficulty of separating the strands of the product duplex. Here, we report a prebiotically plausible approach to strand displacement synthesis in which short 'invader' oligonucleotides unwind an RNA duplex through a toehold/branch migration mechanism, allowing non-enzymatic primer extension on a template that was previously occupied by its complementary strand. Kinetic studies of single-step reactions suggest that following invader binding, branch migration results in a 2:3 partition of the template between open and closed states. Finally, we demonstrate continued primer extension with strand displacement by employing activated 3'-aminonucleotides, a more reactive proxy for ribonucleotides. Our study suggests that complete cycles of non-enzymatic replication of the primordial genetic material may have been facilitated by short RNA oligonucleotides.
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Affiliation(s)
- Lijun Zhou
- Department of Molecular BiologyHoward Hughes Medical Institute, Massachusetts General HospitalBostonUnited States
- Center for Computational and IntegrativeBiologyMassachusetts General HospitalBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Seohyun Chris Kim
- Department of Molecular BiologyHoward Hughes Medical Institute, Massachusetts General HospitalBostonUnited States
- Center for Computational and IntegrativeBiologyMassachusetts General HospitalBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Katherine H Ho
- Department of Chemistry and Chemical BiologyHarvard UniversityCambridgeUnited States
| | - Derek K O'Flaherty
- Department of Molecular BiologyHoward Hughes Medical Institute, Massachusetts General HospitalBostonUnited States
- Center for Computational and IntegrativeBiologyMassachusetts General HospitalBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Constantin Giurgiu
- Department of Chemistry and Chemical BiologyHarvard UniversityCambridgeUnited States
| | - Tom H Wright
- Department of Molecular BiologyHoward Hughes Medical Institute, Massachusetts General HospitalBostonUnited States
- Center for Computational and IntegrativeBiologyMassachusetts General HospitalBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Jack W Szostak
- Department of Molecular BiologyHoward Hughes Medical Institute, Massachusetts General HospitalBostonUnited States
- Center for Computational and IntegrativeBiologyMassachusetts General HospitalBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
- Department of Chemistry and Chemical BiologyHarvard UniversityCambridgeUnited States
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18
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Rodríguez-Serrano AF, Hsing IM. 110th Anniversary: Engineered Ribonucleic Acid Control Elements as Biosensors for in Vitro Diagnostics. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b03963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alan F. Rodríguez-Serrano
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - I-Ming Hsing
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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19
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Shelke SA, Shao Y, Laski A, Koirala D, Weissman BP, Fuller JR, Tan X, Constantin TP, Waggoner AS, Bruchez MP, Armitage BA, Piccirilli JA. Structural basis for activation of fluorogenic dyes by an RNA aptamer lacking a G-quadruplex motif. Nat Commun 2018; 9:4542. [PMID: 30382099 PMCID: PMC6208384 DOI: 10.1038/s41467-018-06942-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 09/26/2018] [Indexed: 12/24/2022] Open
Abstract
The DIR2s RNA aptamer, a second-generation, in-vitro selected binder to dimethylindole red (DIR), activates the fluorescence of cyanine dyes, DIR and oxazole thiazole blue (OTB), allowing detection of two well-resolved emission colors. Using Fab BL3-6 and its cognate hairpin as a crystallization module, we solved the crystal structures of both the apo and OTB-SO3 bound forms of DIR2s at 2.0 Å and 1.8 Å resolution, respectively. DIR2s adopts a compact, tuning fork-like architecture comprised of a helix and two short stem-loops oriented in parallel to create the ligand binding site through tertiary interactions. The OTB-SO3 fluorophore binds in a planar conformation to a claw-like structure formed by a purine base-triple, which provides a stacking platform for OTB-SO3, and an unpaired nucleotide, which partially caps the binding site from the top. The absence of a G-quartet or base tetrad makes the DIR2s aptamer unique among fluorogenic RNAs with known 3D structure. The DIR2s RNA aptamer activates the fluorescence of cyanine dyes allowing detection of two well-resolved emission colors. Here authors solve the crystal structures of the apo and OTB-SO3 fluorophore-bound DIR2s and show how the fluorophore ligand is bound.
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Affiliation(s)
- Sandip A Shelke
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Yaming Shao
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Artur Laski
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Deepak Koirala
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | | | - James R Fuller
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Xiaohong Tan
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.,Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Tudor P Constantin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Alan S Waggoner
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.,Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Marcel P Bruchez
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.,Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.,Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Bruce A Armitage
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.,Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Joseph A Piccirilli
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA. .,Department of Chemistry, The University of Chicago, Chicago, IL, 60637, USA.
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20
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Morris FD, Peterson EM, Heemstra JM, Harris JM. Single-Molecule Kinetic Investigation of Cocaine-Dependent Split-Aptamer Assembly. Anal Chem 2018; 90:12964-12970. [PMID: 30280568 DOI: 10.1021/acs.analchem.8b03637] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Aptamers are short nucleic-acid biopolymers selected to have high affinity and specificity for protein or small-molecule target analytes. Aptamers can be engineered into split-aptamer biosensors comprising two nucleic acid strands that coassemble as they bind to a target, resulting in a large signal change from attached molecular probes (e.g., molecular beacons). The kinetics of split-aptamer assembly and their dependence on target recognition are largely unknown; knowledge of these kinetics could help in design and optimization of split-aptamer biosensors. In this work, we measure assembly kinetics of cocaine-dependent split-aptamer molecules using single-molecule fluorescence imaging. Assembly is monitored between a DNA strand tethered to a glass substrate and solutions containing the other strand tagged with a fluorescent label, with varying concentrations of the cocaine analyte. Dissociation rates are measured by tracking individual molecules and measuring their bound lifetimes. Dissociation-time distributions are biexponential, possibly indicating different folded states of the aptamer. The dissociation rate of only the longer-lived complex decreases with cocaine concentration, suggesting that cocaine stabilizes the long-lived aptamer complex. The variation in the slow dissociation rate with cocaine concentration is well described with an equilibrium-binding model, where the dissociation rate approaches a saturation limit consistent with the dissociation-equilibrium constant for cocaine-binding to the split aptamer. This single-molecule methodology provides a sensitive readout of cocaine-binding based on the dissociation kinetics of the split aptamer, allowing one to distinguish target-dependent aptamer assembly from background assembly. This methodology could be used to study other systems where target association affects the stability of aptamer duplexes.
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Affiliation(s)
- Frances D Morris
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , United States
| | - Eric M Peterson
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , United States
| | - Jennifer M Heemstra
- Department of Chemistry , Emory University , 1515 Dickey Drive , Atlanta , Georgia 30322 , United States
| | - Joel M Harris
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , United States
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21
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Karunanayake Mudiyanselage APKK, Yu Q, Leon-Duque MA, Zhao B, Wu R, You M. Genetically Encoded Catalytic Hairpin Assembly for Sensitive RNA Imaging in Live Cells. J Am Chem Soc 2018; 140:8739-8745. [PMID: 29944357 PMCID: PMC6201751 DOI: 10.1021/jacs.8b03956] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
DNA and RNA nanotechnology has been used for the development of dynamic molecular devices. In particular, programmable enzyme-free nucleic acid circuits, such as catalytic hairpin assembly, have been demonstrated as useful tools for bioanalysis and to scale up system complexity to an extent beyond current cellular genetic circuits. However, the intracellular functions of most synthetic nucleic acid circuits have been hindered by challenges in the biological delivery and degradation. On the other hand, genetically encoded and transcribed RNA circuits emerge as alternative powerful tools for long-term embedded cellular analysis and regulation. Herein, we reported a genetically encoded RNA-based catalytic hairpin assembly circuit for sensitive RNA imaging inside living cells. The split version of Broccoli, a fluorogenic RNA aptamer, was used as the reporter. One target RNA can catalytically trigger the fluorescence from tens-to-hundreds of Broccoli. As a result, target RNAs can be sensitively detected. We have further engineered our circuit to allow easy programming to image various target RNA sequences. This design principle opens the arena for developing a large variety of genetically encoded RNA circuits for cellular applications.
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Affiliation(s)
| | - Qikun Yu
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Mark A. Leon-Duque
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Bin Zhao
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Rigumula Wu
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Mingxu You
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
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22
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Morse DP, Nevins CE, Aggrey-Fynn J, Bravo RJ, Pfaeffle HOI, Laney JE. Sensitive and specific detection of ligands using engineered riboswitches. J Biotechnol 2018. [PMID: 29518463 DOI: 10.1016/j.jbiotec.2018.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Riboswitches are RNA elements found in non-coding regions of messenger RNAs that regulate gene expression through a ligand-triggered conformational change. Riboswitches typically bind tightly and specifically to their ligands, so they have the potential to serve as highly effective sensors in vitro. In B. subtilis and other gram-positive bacteria, purine nucleotide synthesis is regulated by riboswitches that bind to guanine. We modified the xpt-pbuX guanine riboswitch for use in a fluorescence quenching assay that allowed us to specifically detect and quantify guanine in vitro. Using this assay, we reproducibly detected as little as 5 nM guanine. We then produced sensors for 2'-deoxyguanosine and cyclic diguanylate (c-diGMP) by appending the P1 stem of the guanine riboswitch to the ligand-binding domains of a 2'-deoxyguanosine riboswitch and a c-diGMP riboswitch. These hybrid sensors could detect 15 nM 2'-deoxyguanosine and 3 nM c-diGMP, respectively. Each sensor retained the ligand specificity of its corresponding natural riboswitch. In order to extend the utility of our approach, we developed a strategy for the in vitro selection of sensors with novel ligand specificity. Here we report a proof-of-principle experiment that demonstrated the feasibility of our selection strategy.
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Affiliation(s)
- Daniel P Morse
- Department of Chemistry, United States Naval Academy, Annapolis, MD 21402, USA.
| | - Colin E Nevins
- Department of Chemistry, United States Naval Academy, Annapolis, MD 21402, USA
| | - Joana Aggrey-Fynn
- Department of Biochemistry, Cell, and Molecular Biology, University of Ghana, Accra, Ghana
| | - Rick J Bravo
- Department of Chemistry, United States Naval Academy, Annapolis, MD 21402, USA
| | - Herman O I Pfaeffle
- Department of Chemistry, United States Naval Academy, Annapolis, MD 21402, USA
| | - Jess E Laney
- Department of Chemistry, United States Naval Academy, Annapolis, MD 21402, USA
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23
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Chen J, Shang B, Zhang H, Zhu Z, Chen L, Wang H, Ran F, Chen Q, Chen J. Enzyme-free ultrasensitive fluorescence detection of epithelial cell adhesion molecules based on a toehold-aided DNA recycling amplification strategy. RSC Adv 2018; 8:14798-14805. [PMID: 35541343 PMCID: PMC9079946 DOI: 10.1039/c8ra01362d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/04/2018] [Indexed: 01/13/2023] Open
Abstract
Epithelial cell adhesion molecules (EpCAMs) play a significant role in tumorigenesis and tumor development. EpCAMs are considered to be tumor signaling molecules for cancer diagnosis, prognosis and therapy. Herein, an enzyme-free and highly sensitive fluorescent biosensor, with a combined aptamer-based EpCAM recognition and toehold-aided DNA recycling amplification strategy, was developed for sensitive and specific fluorescence detection of EpCAMs. Due to highly specific binding between EpCAMs and corresponding aptamers, strand a, which is released from the complex of aptamer/strand a in the presence of EpCAMs which is bound to the corresponding aptamer, triggered the toehold-mediated strand displacement process. An amplified fluorescent signal was achieved by recycling strand a for ultrasensitive EpCAM detection with a detection limit as low as 0.1 ng mL−1, which was comparable or superior to that of reported immunoassays and biosensor strategies. In addition, high selectivity towards EpCAMs was exhibited when other proteins were selected as control proteins. Finally, this strategy was successfully used for the ultrasensitive fluorescence detection of EpCAMs in human serum samples with satisfactory results. Importantly, the present strategy may be also expanded for the detection of other targets using the corresponding aptamers. A fluorescent biosensor with a combined aptamer-based EpCAM recognition and toehold-aided DNA recycling amplification strategy was developed.![]()
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Affiliation(s)
- Jishun Chen
- Affiliated Dongfeng Hospital
- Hubei University of Medicine
- Hubei Shiyan 442008
- China
| | - Bing Shang
- Affiliated Dongfeng Hospital
- Hubei University of Medicine
- Hubei Shiyan 442008
- China
| | - Hua Zhang
- Affiliated Dongfeng Hospital
- Hubei University of Medicine
- Hubei Shiyan 442008
- China
| | - Zhengpeng Zhu
- Affiliated Dongfeng Hospital
- Hubei University of Medicine
- Hubei Shiyan 442008
- China
| | - Long Chen
- Affiliated Dongfeng Hospital
- Hubei University of Medicine
- Hubei Shiyan 442008
- China
| | - Hongmei Wang
- Affiliated Dongfeng Hospital
- Hubei University of Medicine
- Hubei Shiyan 442008
- China
| | - Fengying Ran
- Affiliated Dongfeng Hospital
- Hubei University of Medicine
- Hubei Shiyan 442008
- China
| | - Qinhua Chen
- Affiliated Dongfeng Hospital
- Hubei University of Medicine
- Hubei Shiyan 442008
- China
| | - Jun Chen
- Affiliated Dongfeng Hospital
- Hubei University of Medicine
- Hubei Shiyan 442008
- China
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24
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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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25
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Bertucci A, Porchetta A, Ricci F. Antibody-Templated Assembly of an RNA Mimic of Green Fluorescent Protein. Anal Chem 2017; 90:1049-1053. [PMID: 29131585 DOI: 10.1021/acs.analchem.7b02102] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
One of the most intriguing ways through which nature achieves regulation of biological pathways encompasses the coordination of noncovalent interactions that bring biomolecules to be colocalized in a designated restricted space. Inspired by this mechanism, we have explored the possibility of using antibodies as bivalent biomolecular substrates for the templated assembly of a functional RNA structure. We have developed a biosupramolecular complementation assay by assembling a fluorescent Spinach aptamer, which is a synthetic RNA mimic of the Green Fluorescent Protein, from its split segments. We have employed two antigen-tagged RNA strands that, upon binding to the target antibody, are colocalized in a confined space and can reassemble into the native Spinach conformation, yielding a measurable fluorescence emission as a function of the templating antibody concentration. We have demonstrated the generality of our approach using two different antigen/antibody systems and found that both platforms show high binding affinity, specificity for the target antibody, and enough selectivity to work in crude cellular extracts. This study highlights the potential of biosupramolecular RNA engineering for the development of innovative biomimetic tools for nanobiotechnology and bioanalytical assays.
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Affiliation(s)
- Alessandro Bertucci
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata , Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Alessandro Porchetta
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata , Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Francesco Ricci
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata , Via della Ricerca Scientifica 1, 00133, Rome, Italy
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26
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Trachman RJ, Truong L, Ferré-D'Amaré AR. Structural Principles of Fluorescent RNA Aptamers. Trends Pharmacol Sci 2017; 38:928-939. [PMID: 28728963 DOI: 10.1016/j.tips.2017.06.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/21/2017] [Accepted: 06/21/2017] [Indexed: 11/26/2022]
Abstract
Several aptamer RNAs have been selected in vitro that bind to otherwise weakly fluorescent small molecules and enhance their fluorescence several thousand-fold. By genetically tagging cellular RNAs of interest with these aptamers and soaking cells in their cell-permeable cognate small-molecule fluorophores, it is possible to use them to study RNA localization and trafficking. These aptamers have also been fused to metabolite-binding RNAs to generate fluorescent biosensors. The 3D structures of three unrelated fluorogenic RNAs have been determined, and reveal a shared reliance on base quadruples (tetrads) to constrain the photo-excited chromophore. The structural diversity of fluorogenic RNAs and the chemical diversity of potential fluorophores to be activated are likely to yield a variety of future fluorogenic RNA tags that are optimized for different applications in RNA imaging and in the design of fluorescent RNA biosensors.
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Affiliation(s)
- Robert J Trachman
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, 50 South Drive MSC 8012, Bethesda, MD 20892-8012, USA
| | - Lynda Truong
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, 50 South Drive MSC 8012, Bethesda, MD 20892-8012, USA
| | - Adrian R Ferré-D'Amaré
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, 50 South Drive MSC 8012, Bethesda, MD 20892-8012, USA.
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27
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Smith AL, Kolpashchikov DM. Divide and Control: Comparison of Split and Switch Hybridization Sensors. ChemistrySelect 2017; 2:5427-5431. [PMID: 29372178 PMCID: PMC5777618 DOI: 10.1002/slct.201701179] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Hybridization probes have been intensively used for nucleic acid analysis in medicine, forensics and fundamental research. Instantaneous hybridization probes (IHPs) enable signalling immediately after binding to a targeted DNA or RNA sequences without the need to isolate the probe-target complex (e. g. by gel electrophoresis). The two most common strategies for IHP design are conformational switches and split approach. A conformational switch changes its conformation and produces signal upon hybridization to a target. Split approach uses two (or more) strands that independently or semi independently bind the target and produce an output signal only if all components associate. Here, we compared the performance of split vs switch designs for deoxyribozyme (Dz) hybridization probes under optimal conditions for each of them. The split design was represented by binary Dz (BiDz) probes; while catalytic molecular beacon (CMB) probes represented the switch design. It was found that BiDz were significantly more selective than CMBs in recognition of single base substitution. CMBs produced high background signal when operated at 55°C. An important advantage of BiDz over CMB is more straightforward design and simplicity of assay optimization.
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Affiliation(s)
- Alexandra L Smith
- Chemistry Department, University of Central Florida, 4000 N. Central Florida Ave, Orlando, FL 32826
| | - Dmitry M Kolpashchikov
- Chemistry Department, Burnett School of Biomedical Sciences, National Center for Forensic Science, University of Central Florida, 4000 N. Central Florida Ave, Orlando, FL 32826
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28
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Ausländer S, Ausländer D, Fussenegger M. Synthetische Biologie - die Synthese der Biologie. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201609229] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Simon Ausländer
- Department of Biosystems Science and Engineering; ETH Zürich; Mattenstrasse 26 4058 Basel Schweiz
| | - David Ausländer
- Department of Biosystems Science and Engineering; ETH Zürich; Mattenstrasse 26 4058 Basel Schweiz
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering; ETH Zürich; Mattenstrasse 26 4058 Basel Schweiz
- Faculty of Science; Universität Basel; Mattenstrasse 26 4058 Basel Schweiz
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29
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Ausländer S, Ausländer D, Fussenegger M. Synthetic Biology-The Synthesis of Biology. Angew Chem Int Ed Engl 2017; 56:6396-6419. [PMID: 27943572 DOI: 10.1002/anie.201609229] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/17/2016] [Indexed: 01/01/2023]
Abstract
Synthetic biology concerns the engineering of man-made living biomachines from standardized components that can perform predefined functions in a (self-)controlled manner. Different research strategies and interdisciplinary efforts are pursued to implement engineering principles to biology. The "top-down" strategy exploits nature's incredible diversity of existing, natural parts to construct synthetic compositions of genetic, metabolic, or signaling networks with predictable and controllable properties. This mainly application-driven approach results in living factories that produce drugs, biofuels, biomaterials, and fine chemicals, and results in living pills that are based on engineered cells with the capacity to autonomously detect and treat disease states in vivo. In contrast, the "bottom-up" strategy seeks to be independent of existing living systems by designing biological systems from scratch and synthesizing artificial biological entities not found in nature. This more knowledge-driven approach investigates the reconstruction of minimal biological systems that are capable of performing basic biological phenomena, such as self-organization, self-replication, and self-sustainability. Moreover, the syntheses of artificial biological units, such as synthetic nucleotides or amino acids, and their implementation into polymers inside living cells currently set the boundaries between natural and artificial biological systems. In particular, the in vitro design, synthesis, and transfer of complete genomes into host cells point to the future of synthetic biology: the creation of designer cells with tailored desirable properties for biomedicine and biotechnology.
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Affiliation(s)
- Simon Ausländer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058, Basel, Switzerland
| | - David Ausländer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058, Basel, Switzerland
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058, Basel, Switzerland.,Faculty of Science, University of Basel, Mattenstrasse 26, 4058, Basel, Switzerland
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Dolgosheina EV, Unrau PJ. Fluorophore-binding RNA aptamers and their applications. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:843-851. [PMID: 27501452 DOI: 10.1002/wrna.1383] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/20/2016] [Accepted: 07/07/2016] [Indexed: 12/21/2022]
Abstract
Why image RNA? Of all the biological molecules, RNA exhibits the most diverse range of functions. Evidence suggests that transcription produces a wide range of noncoding RNAs (ncRNAs), both short (e.g., siRNAs, miRNAs) and long (e.g., telomeric RNAs) that regulate many aspects of gene expression, including the epigenetic processes that underlie cell fate determination, polarization, and morphogenesis. All these functions are realized through the exquisite temporal and spatial control of RNA expression levels and the stability of specific RNAs within well-defined sub-cellular compartments. Given the central importance of RNA in dictating cell behavior via gene-related functions, there is a great demand for RNA imaging methods so as to determine the composition of the cellular 'transcriptome' and to acquire a complete spatial-temporal profile of RNA localization. Recent advances in fluorophore-binding RNA aptamers promise to provide exactly this knowledge, which can ultimately advance our understanding of cell function and behavior in conditions of health and disease, and in response to external stimuli. WIREs RNA 2016, 7:843-851. doi: 10.1002/wrna.1383 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Elena V Dolgosheina
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.
| | - Peter J Unrau
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.
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31
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Kikuchi N, Kolpashchikov DM. Split Spinach Aptamer for Highly Selective Recognition of DNA and RNA at Ambient Temperatures. Chembiochem 2016; 17:1589-92. [PMID: 27305425 DOI: 10.1002/cbic.201600323] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Indexed: 12/25/2022]
Abstract
Split spinach aptamer (SSA) probes for fluorescent analysis of nucleic acids were designed and tested. In SSA design, two RNA or RNA/DNA strands hybridized to a specific nucleic acid analyte and formed a binding site for low-fluorescent 3,5-difluoro-4-hydroxybenzylidene imidazolinone (DFHBI) dye, which resulted in up to a 270-fold increase in fluorescence. The major advantage of the SSA over state-of-the art fluorescent probes is high selectivity: it produces only background fluorescence in the presence of a single-base-mismatched analyte, even at room temperature. SSA is therefore a promising tool for label-free analysis of nucleic acids at ambient temperatures.
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Affiliation(s)
- Nanami Kikuchi
- Chemistry Department, University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL, 32816-2366, USA
| | - Dmitry M Kolpashchikov
- Chemistry Department, University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL, 32816-2366, USA.
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32
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Abstract
There is a growing need to enhance our capabilities in medical and environmental diagnostics. Synthetic biologists have begun to focus their biomolecular engineering approaches toward this goal, offering promising results that could lead to the development of new classes of inexpensive, rapidly deployable diagnostics. Many conventional diagnostics rely on antibody-based platforms that, although exquisitely sensitive, are slow and costly to generate and cannot readily confront rapidly emerging pathogens or be applied to orphan diseases. Synthetic biology, with its rational and short design-to-production cycles, has the potential to overcome many of these limitations. Synthetic biology devices, such as engineered gene circuits, bring new capabilities to molecular diagnostics, expanding the molecular detection palette, creating dynamic sensors, and untethering reactions from laboratory equipment. The field is also beginning to move toward in vivo diagnostics, which could provide near real-time surveillance of multiple pathological conditions. Here, we describe current efforts in synthetic biology, focusing on the translation of promising technologies into pragmatic diagnostic tools and platforms.
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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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Aw SS, Tang MX, Teo YN, Cohen SM. A conformation-induced fluorescence method for microRNA detection. Nucleic Acids Res 2016; 44:e92. [PMID: 26951376 PMCID: PMC4889923 DOI: 10.1093/nar/gkw108] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 02/12/2016] [Indexed: 12/19/2022] Open
Abstract
MicroRNAs play important roles in a large variety of biological systems and processes through their regulation of target mRNA expression, and show promise as clinical biomarkers. However, their small size presents challenges for tagging or direct detection. Innovation in techniques to sense and quantify microRNAs may aid research into novel aspects of microRNA biology and contribute to the development of diagnostics. By introducing an additional stem loop into the fluorescent RNA Spinach and altering its 3' and 5' ends, we have generated a new RNA, Pandan, that functions as the basis for a microRNA sensor. Pandan contains two sequence-variable stem loops that encode complementary sequence for a target microRNA of interest. In its sensor form, it requires the binding of a target microRNA in order to reconstitute the RNA scaffold for fluorophore binding and fluorescence. Binding of the target microRNA resulted in large changes in fluorescence intensity. The median fold change in fluorescence observed for the sensors tested was ∼50-fold. Pandan RNA sensors exhibit good signal-to-noise ratios, and can detect their target microRNAs within complex RNA mixtures.
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Affiliation(s)
- Sherry S Aw
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, 138673, Singapore
| | - Melissa Xm Tang
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, 138673, Singapore
| | - Yin Nah Teo
- Molecular Engineering Laboratory, Biomolecular Sciences Institutes, A*STAR, 61 Biopolis Drive, 138673, Singapore Division of Chemistry and Biological Chemistry, SPMS, Nanyang Technological University, 637371, Singapore
| | - Stephen M Cohen
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, 138673, Singapore Department of Cellular and Molecular Medicine,University of Copenhagen, Blegdamsvej 3, Copenhagen 2200 N, Denmark
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35
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Ausländer S, Fuchs D, Hürlemann S, Ausländer D, Fussenegger M. Engineering a ribozyme cleavage-induced split fluorescent aptamer complementation assay. Nucleic Acids Res 2016; 44:e94. [PMID: 26939886 PMCID: PMC4889925 DOI: 10.1093/nar/gkw117] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 02/16/2016] [Indexed: 12/19/2022] Open
Abstract
Hammerhead ribozymes are self-cleaving RNA molecules capable of regulating gene expression in living cells. Their cleavage performance is strongly influenced by intra-molecular loop–loop interactions, a feature not readily accessible through modern prediction algorithms. Ribozyme engineering and efficient implementation of ribozyme-based genetic switches requires detailed knowledge of individual self-cleavage performances. By rational design, we devised fluorescent aptamer-ribozyme RNA architectures that allow for the real-time measurement of ribozyme self-cleavage activity in vitro. The engineered nucleic acid molecules implement a split Spinach aptamer sequence that is made accessible for strand displacement upon ribozyme self-cleavage, thereby complementing the fluorescent Spinach aptamer. This fully RNA-based ribozyme performance assay correlates ribozyme cleavage activity with Spinach fluorescence to provide a rapid and straightforward technology for the validation of loop–loop interactions in hammerhead ribozymes.
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Affiliation(s)
- Simon Ausländer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - David Fuchs
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Samuel Hürlemann
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - David Ausländer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, CH-4058 Basel, Switzerland Faculty of Science, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland
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36
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Autour A, Westhof E, Ryckelynck M. iSpinach: a fluorogenic RNA aptamer optimized for in vitro applications. Nucleic Acids Res 2016; 44:2491-500. [PMID: 26932363 PMCID: PMC4824111 DOI: 10.1093/nar/gkw083] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/01/2016] [Indexed: 01/03/2023] Open
Abstract
Using random mutagenesis and high throughput screening by microfluidic-assisted In Vitro Compartmentalization, we report the isolation of an order of magnitude times brighter mutants of the light-up RNA aptamers Spinach that are far less salt-sensitive and with a much higher thermal stability than the parent molecule. Further engineering gave iSpinach, a molecule with folding and fluorescence properties surpassing those of all currently known aptamer based on the fluorogenic co-factor 3,5-difluoro-4-hydroxybenzylidene imidazolinone (DFHBI). We illustrate the potential of iSpinach in a new sensitive and high throughput-compatible fluorogenic assay that measures co-transcriptionally the catalytic constant (kcat) of a model ribozyme.
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Affiliation(s)
- Alexis Autour
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de biologie moléculaire et cellulaire du CNRS, 15 rue René Descartes, 67084, Strasbourg, France
| | - Eric Westhof
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de biologie moléculaire et cellulaire du CNRS, 15 rue René Descartes, 67084, Strasbourg, France
| | - Michael Ryckelynck
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de biologie moléculaire et cellulaire du CNRS, 15 rue René Descartes, 67084, Strasbourg, France
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Martini L, Ellington AD, Mansy SS. An in vitro selection for small molecule induced switching RNA molecules. Methods 2016; 106:51-7. [PMID: 26899430 DOI: 10.1016/j.ymeth.2016.02.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 02/12/2016] [Accepted: 02/17/2016] [Indexed: 10/22/2022] Open
Abstract
The selection of RNA and DNA aptamers now has a long history. However, the ability to directly select for conformational changes upon ligand binding has remained elusive. These difficulties have stymied attempts at making small molecule responsive strand displacement circuitry as well as synthetic riboswitches. Herein we present a detailed strand displacement based selection protocol to directly select for RNA molecules with switching activity. The library was based on a previously selected thiamine pyrophosphate riboswitch. The fully in vitro methodology gave sequences that showed strong strand displacement activity in the presence of thiamine pyrophosphate. Further, the selected sequences possessed riboswitch activity similar to that of natural riboswitches. The presented methodology should aid in the design of more complex, environmentally responsive strand displacement circuitry and in the selection of riboswitches responsive to toxic ligands.
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Affiliation(s)
- Laura Martini
- CIBIO, University of Trento, Via Sommarive 9, 38123 Povo, Italy
| | - Andrew D Ellington
- Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA.
| | - Sheref S Mansy
- CIBIO, University of Trento, Via Sommarive 9, 38123 Povo, Italy.
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38
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DasGupta S, Shelke SA, Li NS, Piccirilli JA. Spinach RNA aptamer detects lead(II) with high selectivity. Chem Commun (Camb) 2016; 51:9034-7. [PMID: 25940073 DOI: 10.1039/c5cc01526j] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spinach RNA aptamer contains a G-quadruplex motif that serves as a platform for binding and fluorescence activation of a GFP-like fluorophore. Here we show that Pb(2+) induces formation of Spinach's G-quadruplex and activates fluorescence with high selectivity and sensitivity. This device establishes the first example of an RNA-based sensor that provides a simple and inexpensive tool for Pb(2+) detection.
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Affiliation(s)
- Saurja DasGupta
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA.
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39
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Tools and Principles for Microbial Gene Circuit Engineering. J Mol Biol 2016; 428:862-88. [DOI: 10.1016/j.jmb.2015.10.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 12/26/2022]
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40
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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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41
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Martini L, Meyer AJ, Ellefson JW, Milligan JN, Forlin M, Ellington AD, Mansy SS. In Vitro Selection for Small-Molecule-Triggered Strand Displacement and Riboswitch Activity. ACS Synth Biol 2015; 4:1144-50. [PMID: 25978303 DOI: 10.1021/acssynbio.5b00054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
An in vitro selection method for ligand-responsive RNA sensors was developed that exploited strand displacement reactions. The RNA library was based on the thiamine pyrophosphate (TPP) riboswitch, and RNA sequences capable of hybridizing to a target duplex DNA in a TPP regulated manner were identified. After three rounds of selection, RNA molecules that mediated a strand exchange reaction upon TPP binding were enriched. The enriched sequences also showed riboswitch activity. Our results demonstrated that small-molecule-responsive nucleic acid sensors can be selected to control the activity of target nucleic acid circuitry.
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Affiliation(s)
- Laura Martini
- CIBIO, University of Trento, Via Sommarive 9, 38123 Povo, Italy
| | - Adam J. Meyer
- Department
of Chemistry and Biochemistry, Institute for Cellular and Molecular
Biology, Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, Texas 78712, United States
| | - Jared W. Ellefson
- Department
of Chemistry and Biochemistry, Institute for Cellular and Molecular
Biology, Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, Texas 78712, United States
| | - John N. Milligan
- Department
of Chemistry and Biochemistry, Institute for Cellular and Molecular
Biology, Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, Texas 78712, United States
| | - Michele Forlin
- CIBIO, University of Trento, Via Sommarive 9, 38123 Povo, Italy
| | - Andrew D. Ellington
- Department
of Chemistry and Biochemistry, Institute for Cellular and Molecular
Biology, Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, Texas 78712, United States
| | - Sheref S. Mansy
- CIBIO, University of Trento, Via Sommarive 9, 38123 Povo, Italy
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42
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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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43
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Abstract
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We designed an in vitro signal amplification circuit
that takes a short RNA input that catalytically activates the Spinach
RNA aptamer to produce a fluorescent output. The circuit consists
of three RNA strands: an internally blocked Spinach aptamer, a fuel
strand, and an input strand (catalyst), as well as the Spinach aptamer
ligand 3,5-difluoro-4-hydroxylbenzylidene imidazolinone (DFHBI). The
input strand initially displaces the internal inhibitory strand to
activate the fluorescent aptamer while exposing a toehold to which
the fuel strand can bind to further displace and recycle the input
strand. Under a favorable condition, one input strand was able to
activate up to five molecules of the internally blocked Spinach aptamer
in 185 min at 30 °C. The simple RNA circuit reported here serves
as a model for catalytic activation of arbitrary RNA effectors by
chemical triggers.
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Affiliation(s)
- Farhima Akter
- Department
of Biomedical Engineering, University of California, Davis 451
Health Sciences Drive, Davis, California 95616, United States
| | - Yohei Yokobayashi
- Department
of Biomedical Engineering, University of California, Davis 451
Health Sciences Drive, Davis, California 95616, United States
- Nucleic
Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
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