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Eisenhut P, Marx N, Borsi G, Papež M, Ruggeri C, Baumann M, Borth N. Corrigendum to "Manipulating gene expression levels in mammalian cell factories: An outline of synthetic molecular toolboxes to achieve multiplexed control" [New Biotechnol 79 (2024) 1-19]. N Biotechnol 2024; 84:30-36. [PMID: 39332183 DOI: 10.1016/j.nbt.2024.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2024]
Affiliation(s)
- Peter Eisenhut
- Austrian Centre of Industrial Biotechnology (acib GmbH), Muthgasse 11, 1190 Vienna, Austria
| | - Nicolas Marx
- BOKU University of Natural Resources and Life Sciences, Institute of Animal Cell Technology and Systems Biology, Muthgasse 18, 1190 Vienna, Austria.
| | - Giulia Borsi
- BOKU University of Natural Resources and Life Sciences, Institute of Animal Cell Technology and Systems Biology, Muthgasse 18, 1190 Vienna, Austria
| | - Maja Papež
- Austrian Centre of Industrial Biotechnology (acib GmbH), Muthgasse 11, 1190 Vienna, Austria; BOKU University of Natural Resources and Life Sciences, Institute of Animal Cell Technology and Systems Biology, Muthgasse 18, 1190 Vienna, Austria
| | - Caterina Ruggeri
- BOKU University of Natural Resources and Life Sciences, Institute of Animal Cell Technology and Systems Biology, Muthgasse 18, 1190 Vienna, Austria
| | - Martina Baumann
- Austrian Centre of Industrial Biotechnology (acib GmbH), Muthgasse 11, 1190 Vienna, Austria
| | - Nicole Borth
- Austrian Centre of Industrial Biotechnology (acib GmbH), Muthgasse 11, 1190 Vienna, Austria; BOKU University of Natural Resources and Life Sciences, Institute of Animal Cell Technology and Systems Biology, Muthgasse 18, 1190 Vienna, Austria.
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2
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Nomura Y, Kim N, Zhu B, Hamzah M, Zhang H, Yokobayashi Y. Optimization of Exon-Skipping Riboswitches and Their Applications to Control Mammalian Cell Fate. ACS Synth Biol 2024. [PMID: 39318128 DOI: 10.1021/acssynbio.4c00295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/26/2024]
Abstract
Mammalian riboswitches that can regulate transgene expression via RNA-small molecule interaction have promising applications in medicine and biotechnology, as they involve no protein factors that can induce immunogenic reactions and are not dependent on specially engineered promoters. However, the lack of cell-permeable and low-toxicity small molecules and cognate aptamers that can be exploited as riboswitches and the modest switching performance of mammalian riboswitches have limited their applications. In this study, we systematically optimized the design of a riboswitch that regulates exon skipping via an RNA aptamer that binds ASP2905. We examined two design strategies to modulate the stability of the aptamer base stem that blocks the 5' splice site to fine-tune the riboswitch characteristics. Furthermore, an optimized riboswitch was used to generate a mouse embryonic stem cell line that can be chemically induced to differentiate into myogenic cells by activating Myod1 expression and a human embryonic kidney cell line that can be induced to trigger apoptosis by activating BAX expression. The results demonstrate the tight chemical regulation of transgenes in mammalian cells to control their phenotype without exogenous protein factors.
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Affiliation(s)
- Yoko Nomura
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University Onna, Okinawa 9040495, Japan
| | - Narae Kim
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University Onna, Okinawa 9040495, Japan
| | - Bochen Zhu
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University Onna, Okinawa 9040495, Japan
| | - Muhammad Hamzah
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University Onna, Okinawa 9040495, Japan
| | - Haifeng Zhang
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University Onna, Okinawa 9040495, Japan
| | - Yohei Yokobayashi
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University Onna, Okinawa 9040495, Japan
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3
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Luo L, Jea JDY, Wang Y, Chao PW, Yen L. Control of mammalian gene expression by modulation of polyA signal cleavage at 5' UTR. Nat Biotechnol 2024; 42:1454-1466. [PMID: 38168982 DOI: 10.1038/s41587-023-01989-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/13/2023] [Indexed: 01/05/2024]
Abstract
The ability to control gene expression in mammalian cells is crucial for safe and efficacious gene therapies and for elucidating gene functions. Current gene regulation systems have limitations such as harmful immune responses or low efficiency. We describe the pA regulator, an RNA-based switch that controls mammalian gene expression through modulation of a synthetic polyA signal (PAS) cleavage introduced into the 5' UTR of a transgene. The cleavage is modulated by a 'dual-mechanism'-(1) aptamer clamping to inhibit PAS cleavage and (2) drug-induced alternative splicing that removes the PAS, both activated by drug binding. This RNA-based methodology circumvents the immune responses observed in other systems and achieves a 900-fold induction with an EC50 of 0.5 µg ml-1 tetracycline (Tc), which is well within the FDA-approved dose range. The pA regulator effectively controls the luciferase transgene in live mice and the endogenous CD133 gene in human cells, in a dose-dependent and reversible manner with long-term stability.
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Affiliation(s)
- Liming Luo
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Jocelyn Duen-Ya Jea
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Yan Wang
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Pei-Wen Chao
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Laising Yen
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA.
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA.
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4
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Teixeira AP, Fussenegger M. Synthetic Gene Circuits for Regulation of Next-Generation Cell-Based Therapeutics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309088. [PMID: 38126677 PMCID: PMC10885662 DOI: 10.1002/advs.202309088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Indexed: 12/23/2023]
Abstract
Arming human cells with synthetic gene circuits enables to expand their capacity to execute superior sensing and response actions, offering tremendous potential for innovative cellular therapeutics. This can be achieved by assembling components from an ever-expanding molecular toolkit, incorporating switches based on transcriptional, translational, or post-translational control mechanisms. This review provides examples from the three classes of switches, and discusses their advantages and limitations to regulate the activity of therapeutic cells in vivo. Genetic switches designed to recognize internal disease-associated signals often encode intricate actuation programs that orchestrate a reduction in the sensed signal, establishing a closed-loop architecture. Conversely, switches engineered to detect external molecular or physical cues operate in an open-loop fashion, switching on or off upon signal exposure. The integration of such synthetic gene circuits into the next generation of chimeric antigen receptor T-cells is already enabling precise calibration of immune responses in terms of magnitude and timing, thereby improving the potency and safety of therapeutic cells. Furthermore, pre-clinical engineered cells targeting other chronic diseases are gathering increasing attention, and this review discusses the path forward for achieving clinical success. With synthetic biology at the forefront, cellular therapeutics holds great promise for groundbreaking treatments.
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Affiliation(s)
- Ana P. Teixeira
- Department of Biosystems Science and EngineeringETH ZurichKlingelbergstrasse 48BaselCH‐4056Switzerland
| | - Martin Fussenegger
- Department of Biosystems Science and EngineeringETH ZurichKlingelbergstrasse 48BaselCH‐4056Switzerland
- Faculty of ScienceUniversity of BaselKlingelbergstrasse 48BaselCH‐4056Switzerland
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5
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Takahashi K, Galloway KE. RNA-based controllers for engineering gene and cell therapies. Curr Opin Biotechnol 2024; 85:103026. [PMID: 38052131 PMCID: PMC11214845 DOI: 10.1016/j.copbio.2023.103026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/12/2023] [Accepted: 11/14/2023] [Indexed: 12/07/2023]
Abstract
Engineered RNA-based genetic controllers provide compact, tunable, post-transcriptional gene regulation. As RNA devices are generally small, these devices are portable to DNA and RNA viral vectors. RNA tools have recently expanded to allow reading and editing of endogenous RNAs for profiling and programming of transcriptional states. With their expanded capabilities and highly compact, modular, and programmable nature, RNA-based controllers will support greater safety, efficacy, and performance in gene and cell-based therapies. In this review, we highlight RNA-based controllers and their potential as user-guided and autonomous systems for control of gene and cell-based therapies.
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Affiliation(s)
- Kei Takahashi
- Department of Chemical Engineering, MIT, 25 Ames St., Cambridge, MA 02139, USA
| | - Kate E Galloway
- Department of Chemical Engineering, MIT, 25 Ames St., Cambridge, MA 02139, USA.
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6
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Kläge D, Müller E, Hartig JS. A comparative survey of the influence of small self-cleaving ribozymes on gene expression in human cell culture. RNA Biol 2024; 21:1-11. [PMID: 38146121 PMCID: PMC10761166 DOI: 10.1080/15476286.2023.2296203] [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] [Accepted: 12/13/2023] [Indexed: 12/27/2023] Open
Abstract
Self-cleaving ribozymes are versatile tools for synthetic biologists when it comes to controlling gene expression. Up to date, 12 different classes are known, and over the past decades more and more details about their structure, cleavage mechanisms and natural environments have been uncovered. However, when these motifs are applied to mammalian gene expression constructs, the outcome can often be unexpected. A variety of factors, such as surrounding sequences and positioning of the ribozyme influences the activity and hence performance of catalytic RNAs. While some information about the efficiency of individual ribozymes (each tested in specific contexts) is known, general trends obtained from standardized, comparable experiments are lacking, complicating decisions such as which ribozyme to choose and where to insert it into the target mRNA. In many cases, application-specific optimization is required, which can be very laborious. Here, we systematically compared different classes of ribozymes within the 3'-UTR of a given reporter gene. We then examined position-dependent effects of the best-performing ribozymes. Moreover, we tested additional variants of already widely used hammerhead ribozymes originating from various organisms. We were able to identify functional structures suited for aptazyme design and generated highly efficient hammerhead ribozyme variants originating from the human genome. The present dataset will aide decisions about how to apply ribozymes for affecting gene expression as well as for developing ribozyme-based switches for controlling gene expression in human cells.
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Affiliation(s)
- Dennis Kläge
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Konstanz, Germany
| | - Elisabeth Müller
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Konstanz, Germany
| | - Jörg S. Hartig
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Konstanz, Germany
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7
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Chern KJ, Nettesheim ER, Reid CA, Li NW, Marcoe GJ, Lipinski DM. Prostaglandin-based rAAV-mediated glaucoma gene therapy in Brown Norway rats. Commun Biol 2022; 5:1169. [PMID: 36329259 PMCID: PMC9633612 DOI: 10.1038/s42003-022-04134-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022] Open
Abstract
Prostaglandin analogs are first-line treatments for open angle glaucoma and while effective at lowering intraocular pressure, they are undermined by patient non-compliance, causing atrophy of the optic nerve and severe visual impairment. Herein, we evaluate the safety and efficacy of a recombinant adeno-associated viral vector-mediated gene therapy aimed at permanently lowering intraocular pressure through de novo biosynthesis of prostaglandin F2α within the anterior chamber. This study demonstrated a dose dependent reduction in intraocular pressure in normotensive Brown Norway rats maintained over 12-months. Crucially, therapy could be temporarily halted through off-type riboswitch activation, reverting intraocular pressure to normal. Longitudinal multimodal imaging, electrophysiology, and post-mortem histology revealed the therapy was well tolerated at low and medium doses, with no major adverse effects to anterior chamber health, offering a promising alternative to current treatment strategies leading to clinically relevant reductions in intraocular pressure without the need for adherence to a daily treatment regimen.
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Affiliation(s)
- Kristina J Chern
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Emily R Nettesheim
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Christopher A Reid
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Nathan W Li
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Gavin J Marcoe
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Daniel M Lipinski
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA.
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8
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Hoetzel J, Suess B. Structural changes in aptamers are essential for synthetic riboswitch engineering. J Mol Biol 2022; 434:167631. [PMID: 35595164 DOI: 10.1016/j.jmb.2022.167631] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/05/2022] [Accepted: 05/07/2022] [Indexed: 11/19/2022]
Abstract
Synthetic riboswitches are powerful tools in synthetic biology in which sensing and execution are consolidated in a single RNA molecule. By using SELEX to select aptamers in vitro, synthetic riboswitches can in theory be engineered against any ligand of choice. Surprisingly, very few in vitro selected aptamers have been used for the engineering of synthetic riboswitches. In-depth studies of these aptamers suggest that the key characteristics of such regulatory active RNAs are their structural switching abilities and their binding dynamics. Conventional SELEX approaches seem to be inadequate to select for these characteristics, which may explain the lack of in vitro selected aptamers suited for engineering of synthetic riboswitches. In this review, we explore the functional principles of synthetic riboswitches, identify key characteristics of regulatory active in vitro selected aptamers and integrate these findings in context with available in vitro selection methods. Based on these insights, we propose to use a combination of capture-SELEX and subsequent functional screening for a more successful in vitro selection of aptamers that can be applied for the engineering of synthetic riboswitches.
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Affiliation(s)
- Janis Hoetzel
- Department of Biology, Technical University of Darmstadt, Schnittspahnstraße 10, D-64287 Darmstadt, Germany. https://www.twitter.com/J_Hoetzel
| | - Beatrix Suess
- Department of Biology, Technical University of Darmstadt, Schnittspahnstraße 10, D-64287 Darmstadt, Germany; Center for Synthetic Biology, Technical University of Darmstadt, Germany.
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9
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Synthetic RNA-based post-transcriptional expression control methods and genetic circuits. Adv Drug Deliv Rev 2022; 184:114196. [PMID: 35288218 DOI: 10.1016/j.addr.2022.114196] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/27/2022] [Accepted: 03/08/2022] [Indexed: 12/19/2022]
Abstract
RNA-based synthetic genetic circuits provide an alternative for traditional transcription-based circuits in applications where genomic integration is to be avoided. Incorporating various post-transcriptional control methods into such circuits allows for controlling the behaviour of the circuit through the detection of certain biomolecular inputs or reconstituting defined circuit behaviours, thus manipulating cellular functions. In this review, recent developments of various types of post-transcriptional control methods in mammalian cells are discussed as well as auxiliary components that allow for the creation and development of mRNA-based switches. How such post-transcriptional switches are combined into synthetic circuits as well as their applications in biomedical and preclinical settings are also described. Finally, we examine the challenges that need to be surmounted before RNA-based synthetic circuits can be reliably deployed into clinical settings.
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10
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Kim N, Yokobayashi Y. Novel RNA Viral Vectors for Chemically Regulated Gene Expression in Embryonic Stem Cells. ACS Synth Biol 2021; 10:2959-2967. [PMID: 34676762 DOI: 10.1021/acssynbio.1c00214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
RNA viral vectors that replicate without DNA intermediates are attractive platforms for manipulation of cells for biomedical and veterinary applications because they have minimal risk of chromosomal integration. Vesicular stomatitis virus (VSV) vectors are among the most well-studied RNA viral vectors due to their low pathogenicity to humans and ability to express transgenes at high levels for weeks to months. However, their applications have been mostly limited to oncolytic and vaccine vectors due to their cytopathogenicity. We discovered two mutations in the VSV vector that synergistically confer improved stability in mouse embryonic stem cells (ESCs) with markedly lower cytopathic effects. We also demonstrated chemical regulation of transgene expression through embedded riboswitches. The ESCs infected with the mutant vector were shown to maintain pluripotency. This new vector sets the stage for precise regulation of gene expression in ESCs to produce a variety of differentiated cells without chromosomal alteration.
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Affiliation(s)
- Narae Kim
- 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
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11
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Oesinghaus L, Simmel FC. Kontrolle von Genexpression in Säugetierzellen mithilfe von parallel schaltbaren Guide‐RNAs für Cas12a**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Lukas Oesinghaus
- Physics Department, E14 TU München Am Coulombwall 4a 85748 Garching Deutschland
| | - Friedrich C. Simmel
- Physics Department, E14 TU München Am Coulombwall 4a 85748 Garching Deutschland
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12
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Oesinghaus L, Simmel FC. Controlling Gene Expression in Mammalian Cells Using Multiplexed Conditional Guide RNAs for Cas12a*. Angew Chem Int Ed Engl 2021; 60:23894-23902. [PMID: 34533878 PMCID: PMC8596743 DOI: 10.1002/anie.202107258] [Citation(s) in RCA: 15] [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: 05/31/2021] [Revised: 08/13/2021] [Indexed: 12/26/2022]
Abstract
Spatiotemporal control of the activity of CRISPR-associated (Cas) proteins is of considerable interest for basic research and therapeutics. Here, we show that conditional guide RNAs (gRNAs) for Cas12a can be transcribed in mammalian cells by RNA polymerase II, followed by activation via input-dependent processing of the 3' tail of the gRNA transcript. We demonstrate processing using an RNA strand displacement mechanism, as well as microRNA-dependent processing, and cleavage by a guanine-responsive ribozyme. We further demonstrate that Cas12a along with several independently switchable gRNAs can be compactly integrated on a single transcript using stabilizing RNA triplexes, providing a route towards Cas12a-based gene regulation constructs with multi-input switching capabilities. The principle is shown to work in HEK and mouse fibroblast cells using luminescence, fluorescence, and is also demonstrated for the conditional upregulation of an endogenous gene.
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Affiliation(s)
- Lukas Oesinghaus
- Physics Department, E14TU MunichAm Coulombwall 4a85748GarchingGermany
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13
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Aptamers in Virology-A Consolidated Review of the Most Recent Advancements in Diagnosis and Therapy. Pharmaceutics 2021; 13:pharmaceutics13101646. [PMID: 34683938 PMCID: PMC8540715 DOI: 10.3390/pharmaceutics13101646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/28/2021] [Accepted: 10/01/2021] [Indexed: 01/05/2023] Open
Abstract
The use of short oligonucleotide or peptide molecules as target-specific aptamers has recently garnered substantial attention in the field of the detection and treatment of viral infections. Based on their high affinity and high specificity to desired targets, their use is on the rise to replace antibodies for the detection of viruses and viral antigens. Furthermore, aptamers inhibit intracellular viral transcription and translation, in addition to restricting viral entry into host cells. This has opened up a plethora of new targets for the research and development of novel vaccines against viruses. Here, we discuss the advances made in aptamer technology for viral diagnosis and therapy in the past decade.
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Peng H, Latifi B, Müller S, Lupták A, Chen IA. Self-cleaving ribozymes: substrate specificity and synthetic biology applications. RSC Chem Biol 2021; 2:1370-1383. [PMID: 34704043 PMCID: PMC8495972 DOI: 10.1039/d0cb00207k] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 06/14/2021] [Indexed: 12/22/2022] Open
Abstract
Various self-cleaving ribozymes appearing in nature catalyze the sequence-specific intramolecular cleavage of RNA and can be engineered to catalyze cleavage of appropriate substrates in an intermolecular fashion, thus acting as true catalysts. The mechanisms of the small, self-cleaving ribozymes have been extensively studied and reviewed previously. Self-cleaving ribozymes can possess high catalytic activity and high substrate specificity; however, substrate specificity is also engineerable within the constraints of the ribozyme structure. While these ribozymes share a common fundamental catalytic mechanism, each ribozyme family has a unique overall architecture and active site organization, indicating that several distinct structures yield this chemical activity. The multitude of catalytic structures, combined with some flexibility in substrate specificity within each family, suggests that such catalytic RNAs, taken together, could access a wide variety of substrates. Here, we give an overview of 10 classes of self-cleaving ribozymes and capture what is understood about their substrate specificity and synthetic applications. Evolution of these ribozymes in an RNA world might be characterized by the emergence of a new ribozyme family followed by rapid adaptation or diversification for specific substrates. Self-cleaving ribozymes have become important tools of synthetic biology. Here we summarize the substrate specificity and applications of the main classes of these ribozymes.![]()
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Affiliation(s)
- Huan Peng
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles CA 90095 USA
| | - Brandon Latifi
- Department of Pharmaceutical Sciences, University of California Irvine CA 92697 USA
| | - Sabine Müller
- Institute for Biochemistry, University Greifswald 17487 Greifswald Germany
| | - Andrej Lupták
- Department of Pharmaceutical Sciences, University of California Irvine CA 92697 USA
| | - Irene A Chen
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles CA 90095 USA
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15
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Tabuchi T, Yokobayashi Y. Cell-free riboswitches. RSC Chem Biol 2021; 2:1430-1440. [PMID: 34704047 PMCID: PMC8496063 DOI: 10.1039/d1cb00138h] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 07/26/2021] [Indexed: 12/16/2022] Open
Abstract
The emerging community of cell-free synthetic biology aspires to build complex biochemical and genetic systems with functions that mimic or even exceed those in living cells. To achieve such functions, cell-free systems must be able to sense and respond to the complex chemical signals within and outside the system. Cell-free riboswitches can detect chemical signals via RNA-ligand interaction and respond by regulating protein synthesis in cell-free protein synthesis systems. In this article, we review synthetic cell-free riboswitches that function in both prokaryotic and eukaryotic cell-free systems reported to date to provide a current perspective on the state of cell-free riboswitch technologies and their limitations.
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Affiliation(s)
- Takeshi Tabuchi
- 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
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16
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Mustafina K, Nomura Y, Rotrattanadumrong R, Yokobayashi Y. Circularly-Permuted Pistol Ribozyme: A Synthetic Ribozyme Scaffold for Mammalian Riboswitches. ACS Synth Biol 2021; 10:2040-2048. [PMID: 34374523 DOI: 10.1021/acssynbio.1c00213] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A small molecule-responsive self-cleaving ribozyme (aptazyme) embedded in the untranslated region of an mRNA functions as a riboswitch that allows chemical regulation of gene expression in mammalian cells. Aptazymes are engineered by fusing a self-cleaving ribozyme with an RNA aptamer that recognizes a small molecule so that the ribozyme is either activated or inhibited in the presence of the small molecule. However, the variety of aptamers, ribozymes, and aptazyme design strategies suitable for mammalian riboswitch applications is still limited. This work focuses on a new ribozyme scaffold for engineering aptazymes and riboswitches that function in mammalian cells. We investigated circularly permuted variants of the pistol ribozyme class (CPP) as a synthetic ribozyme scaffold for mammalian riboswitch applications. Through semirational design and high-throughput screening, we designed guanine and tetracycline activated riboswitches based on three distinct aptazyme architectures, resulting in riboswitches with ON/OFF ratios as high as 8.6. Our work adds CPP to the limited ribozyme scaffold toolbox for mammalian synthetic biology applications and highlights the opportunities in exploring ribozymes beyond natural motifs.
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Affiliation(s)
- Kamila Mustafina
- 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
| | - Rachapun Rotrattanadumrong
- 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
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17
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Tickner ZJ, Farzan M. Riboswitches for Controlled Expression of Therapeutic Transgenes Delivered by Adeno-Associated Viral Vectors. Pharmaceuticals (Basel) 2021; 14:ph14060554. [PMID: 34200913 PMCID: PMC8230432 DOI: 10.3390/ph14060554] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 05/28/2021] [Accepted: 06/04/2021] [Indexed: 11/16/2022] Open
Abstract
Vectors developed from adeno-associated virus (AAV) are powerful tools for in vivo transgene delivery in both humans and animal models, and several AAV-delivered gene therapies are currently approved for clinical use. However, AAV-mediated gene therapy still faces several challenges, including limited vector packaging capacity and the need for a safe, effective method for controlling transgene expression during and after delivery. Riboswitches, RNA elements which control gene expression in response to ligand binding, are attractive candidates for regulating expression of AAV-delivered transgene therapeutics because of their small genomic footprints and non-immunogenicity compared to protein-based expression control systems. In addition, the ligand-sensing aptamer domains of many riboswitches can be exchanged in a modular fashion to allow regulation by a variety of small molecules, proteins, and oligonucleotides. Riboswitches have been used to regulate AAV-delivered transgene therapeutics in animal models, and recently developed screening and selection methods allow rapid isolation of riboswitches with novel ligands and improved performance in mammalian cells. This review discusses the advantages of riboswitches in the context of AAV-delivered gene therapy, the subsets of riboswitch mechanisms which have been shown to function in human cells and animal models, recent progress in riboswitch isolation and optimization, and several examples of AAV-delivered therapeutic systems which might be improved by riboswitch regulation.
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Affiliation(s)
- Zachary J. Tickner
- Department of Immunology and Microbiology, the Scripps Research Institute, Jupiter, FL 33458, USA;
- Correspondence:
| | - Michael Farzan
- Department of Immunology and Microbiology, the Scripps Research Institute, Jupiter, FL 33458, USA;
- Emmune, Inc., Jupiter, FL 33458, USA
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18
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Smart Nucleic Acids as Future Therapeutics. Trends Biotechnol 2021; 39:1289-1307. [PMID: 33980422 DOI: 10.1016/j.tibtech.2021.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/23/2021] [Accepted: 03/29/2021] [Indexed: 11/23/2022]
Abstract
Nucleic acid therapeutics (NATs) hold promise in treating undruggable diseases and are recognized as the third major category of therapeutics in addition to small molecules and antibodies. Despite the milestones that NATs have made in clinical translation over the past decade, one important challenge pertains to increasing the specificity of this class of drugs. Activating NATs exclusively in disease-causing cells is highly desirable because it will safely broaden the application of NATs to a wider range of clinical indications. Smart NATs are triggered through a photo-uncaging reaction or a specific molecular input such as a transcript, protein, or small molecule, thus complementing the current strategy of targeting cells and tissues with receptor-specific ligands to enhance specificity. This review summarizes the programmable modalities that have been incorporated into NATs to build in responsive behaviors. We discuss the various inputs, transduction mechanisms, and output response functions that have been demonstrated to date.
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19
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Zhuang C, Zhuang C, Zhou Q, Huang X, Gui Y, Lai Y, Yang S. Engineered CRISPR/Cas13d Sensing hTERT Selectively Inhibits the Progression of Bladder Cancer In Vitro. Front Mol Biosci 2021; 8:646412. [PMID: 33816560 PMCID: PMC8017217 DOI: 10.3389/fmolb.2021.646412] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 02/01/2021] [Indexed: 12/12/2022] Open
Abstract
Aptazyme and CRISPR/Cas gene editing system were widely used for regulating gene expression in various diseases, including cancer. This work aimed to reconstruct CRISPR/Cas13d tool for sensing hTERT exclusively based on the new device OFF-switch hTERT aptazyme that was inserted into the 3’ UTR of the Cas13d. In bladder cancer cells, hTERT ligand bound to aptamer in OFF-switch hTERT aptazyme to inhibit the degradation of Cas13d. Results showed that engineered CRISPR/Cas13d sensing hTERT suppressed cell proliferation, migration, invasion and induced cell apoptosis in bladder cancer 5637 and T24 cells without affecting normal HFF cells. In short, we constructed engineered CRISPR/Cas13d sensing hTERT selectively inhibited the progression of bladder cancer cells significantly. It may serve as a promising specifically effective therapy for bladder cancer cells.
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Affiliation(s)
- Chengle Zhuang
- Department of Urology, Peking University Shenzhen Hospital, Shenzhen, China
| | - Changshui Zhuang
- Department of Urology, Union Shenzhen Hospital, Huazhong University of Science and Technology, Shenzhen, China
| | - Qun Zhou
- Department of Urology, the Affiliated Nanhua Hospital of University of South China, Hengyang, China
| | - Xueting Huang
- Department of Nephrorheumatology, Shenzhen Yantian District People's Hospital, Shenzhen, China
| | - Yaoting Gui
- Department of Urology, Peking University Shenzhen Hospital, Shenzhen, China
| | - Yongqing Lai
- Department of Urology, Peking University Shenzhen Hospital, Shenzhen, China
| | - Shangqi Yang
- Department of Urology, Peking University Shenzhen Hospital, Shenzhen, China
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20
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Abstract
This chapter describes a screening strategy to engineer synthetic riboswitches that can chemically regulate gene expression in mammalian cells. Riboswitch libraries are constructed by randomizing the key nucleotides that couple the molecular recognition function of an aptamer with the self-cleavage activity of a ribozyme. The allosteric ribozyme (aptazyme) candidates are cloned in the 3' untranslated region (UTR) of a reporter gene mRNA. The plasmid-encoded riboswitch candidates are transfected into a mammalian cell line to screen for the desired riboswitch function. Furthermore, multiple aptazymes can be cloned into the 3' UTR of a desired gene to obtain a logic gate response to multiple chemical signals. This screening strategy complements other methods to engineer robust mammalian riboswitches to control gene expression.
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Affiliation(s)
- Yoko Nomura
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Yohei Yokobayashi
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan.
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21
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Abstract
Some long non-coding RNA (lncRNA) genes encode a functional RNA product, whereas others act as DNA elements or via the act of transcription . We describe here a ribozyme-based approach to deplete an endogenous lncRNA in mouse embryonic stem cells, with minimal disruption of its gene. This enables the role of the lncRNA product to be tested.
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Affiliation(s)
- Alex C Tuck
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Marc Bühler
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
- University of Basel, Basel, Switzerland.
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22
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Yokobayashi Y. High-Throughput Analysis and Engineering of Ribozymes and Deoxyribozymes by Sequencing. Acc Chem Res 2020; 53:2903-2912. [PMID: 33164502 DOI: 10.1021/acs.accounts.0c00546] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ribozymes and deoxyribozymes are catalytic RNA and DNA, respectively, that catalyze chemical reactions such as self-cleavage or ligation reactions. While some ribozymes are found in nature, a larger variety of ribozymes and deoxyribozymes have been discovered by in vitro selection from random sequences. These catalytic nucleic acids, especially ribozymes, are of fundamental interest because they are crucial for the RNA world hypothesis, which suggests that RNA played a central role in both the propagation of genetic information and catalyzing metabolic reactions in primordial life prior to the emergence of proteins and DNA. On the practical side, catalytic nucleic acids have been extensively engineered for various applications, such as biosensors and genetic devices for synthetic biology. Therefore, it is important to gain a deeper understanding of the sequence-function relationships of ribozymes and deoxyribozymes.Mutational analysis, or measurements of activities of catalytic nucleic acid mutants, is one of the most fundamental approaches for that purpose. Mutations that abolish, reduce, retain, or even increase activity provide useful information about nucleic acid catalysts for engineering and other purposes. However, methods for mutational analysis of ribozymes and deoxyribozymes have not evolved much for decades, requiring tedious and low-throughput assays (e.g., gel electrophoresis) of individually prepared mutants. This has prevented researchers from performing quantitative mutational analysis of ribozymes and deoxyribozymes on a large scale.To address this limitation, we developed a massively parallel ribozyme and deoxyribozyme assay strategy that allows >104 assays using high-throughput sequencing (HTS). We used HTS to literally count the number of cleaved (or ligated) and uncleaved (or unligated) ribozyme (or deoxyribozyme) sequences and calculated the activities of each mutant in a reaction mixture. This simple yet powerful strategy was applied to analyze the mutational effects of various natural and synthetic ribozymes and deoxyribozymes at scales impossible for conventional mutational analysis. These large-scale sequence-function data sets were used to better understand the functional consequences of mutations and to engineer ribozymes for practical applications. Furthermore, these newly available data are motivating researchers to employ more rigorous computational methods to extract additional insights such as structural information and nonlinear effects of multiple mutations. The new HTS-based assay strategy is distinct from and complementary to a related strategy that uses HTS to analyze ribozyme and deoxyribozyme populations subjected to in vitro selection. Postselection sequencing can cover a larger sequence space, although it does not directly quantify the activities of ribozyme and deoxyribozyme mutants. With further advances in DNA sequencing technologies and computational methods, there should be more opportunities to harness the power of HTS to deepen our understanding of catalytic nucleic acids and enhance our ability to engineer them for even more applications.
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Affiliation(s)
- Yohei Yokobayashi
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
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23
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Spöring M, Boneberg R, Hartig JS. Aptamer-Mediated Control of Polyadenylation for Gene Expression Regulation in Mammalian Cells. ACS Synth Biol 2020; 9:3008-3018. [PMID: 33108164 DOI: 10.1021/acssynbio.0c00222] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Small aptamer-based regulatory devices can be designed to control a range of RNA-dependent cellular processes and emerged as promising tools for fine-tuning gene expression in synthetic biology. Here, we design a conceptually new riboswitch device that allows for the conditional regulation of polyadenylation. By making use of ligand-induced sequence occlusion, the system efficiently controls the accessibility of the eukaryotic polyadenylation signal. Undesirable 3'-extended read-through products are counteracted by the downstream insertion of a microRNA target site. We demonstrate the modularity of the system with regard to sensor aptamers and polyadenylation signals used and combine the newly designed riboswitch with well-known aptazymes to yield superior composite systems. In addition, we show that the switches can be used to control alternative polyadenylation. The presented genetic switches require very little coding space and can be easily optimized by rational adjustments of the thermodynamic stability. The polyadenylation riboswitch extends the repertoire of RNA-based regulators and opens new possibilities for the generation of complex synthetic circuits.
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Affiliation(s)
- Maike Spöring
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
- Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Ronja Boneberg
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Jörg S. Hartig
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
- Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
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24
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Strobel B, Düchs MJ, Blazevic D, Rechtsteiner P, Braun C, Baum-Kroker KS, Schmid B, Ciossek T, Gottschling D, Hartig JS, Kreuz S. A Small-Molecule-Responsive Riboswitch Enables Conditional Induction of Viral Vector-Mediated Gene Expression in Mice. ACS Synth Biol 2020; 9:1292-1305. [PMID: 32427483 DOI: 10.1021/acssynbio.9b00410] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Adeno-associated viral (AAV) vector-mediated gene therapy holds great potential for future medical applications. However, to facilitate safer and broader applicability and to enable patient-centric care, therapeutic protein expression should be controllable, ideally by an orally administered drug. The use of protein-based systems is considered rather undesirable, due to potential immunogenicity and the limited coding space of AAV. Ligand-dependent riboswitches, in contrast, are small and characterized by an attractive mode-of-action based on mRNA-self-cleavage, independent of coexpressed foreign protein. While a promising approach, switches available to date have only shown moderate potency in animals. In particular, ON-switches that induce transgene expression upon ligand administration so far have achieved rather disappointing results. Here we present the utilization of the previously described tetracycline-dependent ribozyme K19 for controlling AAV-mediated transgene expression in mice. Using this tool switch, we provide first proof for the feasibility of clinically desired key features, including multiorgan functionality, potent regulation (up to 15-fold induction), reversibility, and the possibility to fine-tune and repeatedly induce expression. The systematic assessment of ligand and reporter protein plasma levels further enabled the characterization of pharmacokinetic-pharmacodynamic relationships. Thus, our results strongly support future efforts to develop engineered riboswitches for applications in clinical gene therapy.
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Affiliation(s)
- Benjamin Strobel
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Matthias J. Düchs
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Dragica Blazevic
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Philipp Rechtsteiner
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Clemens Braun
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Katja S. Baum-Kroker
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Bernhard Schmid
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Thomas Ciossek
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Dirk Gottschling
- Medicinal Chemistry, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Jörg S. Hartig
- Department of Chemistry, University of Konstanz, Konstanz, 78464, Germany
| | - Sebastian Kreuz
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
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25
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Wrist A, Sun W, Summers RM. The Theophylline Aptamer: 25 Years as an Important Tool in Cellular Engineering Research. ACS Synth Biol 2020; 9:682-697. [PMID: 32142605 DOI: 10.1021/acssynbio.9b00475] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The theophylline aptamer was isolated from an oligonucleotide library in 1994. Since that time, the aptamer has found wide utility, particularly in synthetic biology, cellular engineering, and diagnostic applications. The primary application of the theophylline aptamer is in the construction and characterization of synthetic riboswitches for regulation of gene expression. These riboswitches have been used to control cellular motility, regulate carbon metabolism, construct logic gates, screen for mutant enzymes, and control apoptosis. Other applications of the theophylline aptamer in cellular engineering include regulation of RNA interference and genome editing through CRISPR systems. Here we describe the uses of the theophylline aptamer for cellular engineering over the past 25 years. In so doing, we also highlight important synthetic biology applications to control gene expression in a ligand-dependent manner.
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Affiliation(s)
- Alexandra Wrist
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Wanqi Sun
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Ryan M. Summers
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, Alabama 35487, United States
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26
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Strobel B, Spöring M, Klein H, Blazevic D, Rust W, Sayols S, Hartig JS, Kreuz S. High-throughput identification of synthetic riboswitches by barcode-free amplicon-sequencing in human cells. Nat Commun 2020; 11:714. [PMID: 32024835 PMCID: PMC7002664 DOI: 10.1038/s41467-020-14491-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 01/14/2020] [Indexed: 11/10/2022] Open
Abstract
Synthetic riboswitches mediating ligand-dependent RNA cleavage or splicing-modulation represent elegant tools to control gene expression in various applications, including next-generation gene therapy. However, due to the limited understanding of context-dependent structure-function relationships, the identification of functional riboswitches requires large-scale-screening of aptamer-effector-domain designs, which is hampered by the lack of suitable cellular high-throughput methods. Here we describe a fast and broadly applicable method to functionally screen complex riboswitch libraries (~1.8 × 104 constructs) by cDNA-amplicon-sequencing in transiently transfected and stimulated human cells. The self-barcoding nature of each construct enables quantification of differential mRNA levels without additional pre-selection or cDNA-manipulation steps. We apply this method to engineer tetracycline- and guanine-responsive ON- and OFF-switches based on hammerhead, hepatitis-delta-virus and Twister ribozymes as well as U1-snRNP polyadenylation-dependent RNA devices. In summary, our method enables fast and efficient high-throughput riboswitch identification, thereby overcoming a major hurdle in the development cascade for therapeutically applicable gene switches.
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Affiliation(s)
- Benjamin Strobel
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Str. 65, 88397, Biberach an der Riss, Germany
| | - Maike Spöring
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
- Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
| | - Holger Klein
- Computational Biology & Genomics, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Str. 65, 88397, Biberach an der Riss, Germany
| | - Dragica Blazevic
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Str. 65, 88397, Biberach an der Riss, Germany
| | - Werner Rust
- Computational Biology & Genomics, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Str. 65, 88397, Biberach an der Riss, Germany
| | - Sergi Sayols
- Computational Biology & Genomics, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Str. 65, 88397, Biberach an der Riss, Germany
| | - Jörg S Hartig
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
- Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
| | - Sebastian Kreuz
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Str. 65, 88397, Biberach an der Riss, Germany.
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27
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Mustafina K, Fukunaga K, Yokobayashi Y. Design of Mammalian ON-Riboswitches Based on Tandemly Fused Aptamer and Ribozyme. ACS Synth Biol 2020; 9:19-25. [PMID: 31820936 DOI: 10.1021/acssynbio.9b00371] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Self-cleaving ribozymes engineered to be activated or inhibited by a small molecule binding to an RNA aptamer inserted within a ribozyme (aptazymes) have proven to be useful for controlling gene expression in living cells. In mammalian cells, an aptazyme embedded in the 5' or 3' untranslated region of an mRNA functions as a synthetic riboswitch to chemically regulate gene expression. However, the variety of aptazyme architectures and the ribozyme scaffolds that have been used for mammalian riboswitches has been limited. In particular, fewer synthetic riboswitches that activate gene expression in response to a small molecule (ON-switches) in mammalian cells have been reported compared to OFF-switches. In this work, we developed mammalian riboswitches that function as guanine-activated ON-switches based on a novel aptazyme architecture in which an aptamer and a ribozyme are fused in tandem. The riboswitch performance was optimized by fine-tuning the stability of a critical stem that controls the ribozyme structure and function, yielding switches with ON/OFF ratios greater than 6.0. Our new aptazyme architecture expands the RNA device toolbox for controlling gene expression in mammalian cells.
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Affiliation(s)
- Kamila Mustafina
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904 0495, Japan
| | - Keisuke Fukunaga
- 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
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28
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Catalytic RNA, ribozyme, and its applications in synthetic biology. Biotechnol Adv 2019; 37:107452. [DOI: 10.1016/j.biotechadv.2019.107452] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 09/16/2019] [Accepted: 09/17/2019] [Indexed: 12/21/2022]
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29
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Gil N, Ulitsky I. Regulation of gene expression by cis-acting long non-coding RNAs. Nat Rev Genet 2019; 21:102-117. [DOI: 10.1038/s41576-019-0184-5] [Citation(s) in RCA: 296] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2019] [Indexed: 12/14/2022]
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30
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Xiang JS, Kaplan M, Dykstra P, Hinks M, McKeague M, Smolke CD. Massively parallel RNA device engineering in mammalian cells with RNA-Seq. Nat Commun 2019; 10:4327. [PMID: 31548547 PMCID: PMC6757056 DOI: 10.1038/s41467-019-12334-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 08/28/2019] [Indexed: 12/21/2022] Open
Abstract
Synthetic RNA-based genetic devices dynamically control a wide range of gene-regulatory processes across diverse cell types. However, the limited throughput of quantitative assays in mammalian cells has hindered fast iteration and interrogation of sequence space needed to identify new RNA devices. Here we report developing a quantitative, rapid and high-throughput mammalian cell-based RNA-Seq assay to efficiently engineer RNA devices. We identify new ribozyme-based RNA devices that respond to theophylline, hypoxanthine, cyclic-di-GMP, and folinic acid from libraries of ~22,700 sequences in total. The small molecule responsive devices exhibit low basal expression and high activation ratios, significantly expanding our toolset of highly functional ribozyme switches. The large datasets obtained further provide conserved sequence and structure motifs that may be used for rationally guided design. The RNA-Seq approach offers a generally applicable strategy for developing broad classes of RNA devices, thereby advancing the engineering of genetic devices for mammalian systems.
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Affiliation(s)
- Joy S Xiang
- Department of Bioengineering, 443 Via Ortega, MC 4245, Stanford University, Stanford, CA, 94305, USA
| | - Matias Kaplan
- Department of Bioengineering, 443 Via Ortega, MC 4245, Stanford University, Stanford, CA, 94305, USA
| | - Peter Dykstra
- Department of Bioengineering, 443 Via Ortega, MC 4245, Stanford University, Stanford, CA, 94305, USA
| | - Michaela Hinks
- Department of Bioengineering, 443 Via Ortega, MC 4245, Stanford University, Stanford, CA, 94305, USA
| | - Maureen McKeague
- Department of Pharmacology and Therapeutics, McGill University, 3655 Prom. Sir-William-Osler, Montreal, Quebec, H3G 1Y6, Canada
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada
| | - Christina D Smolke
- Department of Bioengineering, 443 Via Ortega, MC 4245, Stanford University, Stanford, CA, 94305, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA.
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31
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Takahashi K, Yokobayashi Y. Reversible Gene Regulation in Mammalian Cells Using Riboswitch-Engineered Vesicular Stomatitis Virus Vector. ACS Synth Biol 2019; 8:1976-1982. [PMID: 31415142 DOI: 10.1021/acssynbio.9b00177] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Synthetic riboswitches based on small molecule-responsive self-cleaving ribozymes (aptazymes) embedded in the untranslated regions (UTRs) allow chemical control of gene expression in mammalian cells. In this work, we used a guanine-responsive aptazyme to control transgene expression from a replication-incompetent vesicular stomatitis virus (VSV) vector. VSV is a nonsegmented, negative-sense, cytoplasmic RNA virus that replicates without DNA intermediates, and its applications for vaccines and oncolytic viral therapy are being explored. By inserting the guanine-activated ribozyme in the 3' UTRs of viral genes and transgenes, GFP expression from the VSV vector in mammalian cells was repressed by as much as 26.8-fold in the presence of guanine. Furthermore, we demonstrated reversible regulation of a transgene (secreted NanoLuc) by adding and withdrawing guanine from the medium over the course of 12 days. In summary, our riboswitch-controlled VSV vector allows robust, long-term, and reversible regulation of gene expression in mammalian cells without the risk of undesirable genomic integration.
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Affiliation(s)
- Kei Takahashi
- 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
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32
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Matsumoto S, Caliskan N, Rodnina MV, Murata A, Nakatani K. Small synthetic molecule-stabilized RNA pseudoknot as an activator for -1 ribosomal frameshifting. Nucleic Acids Res 2019; 46:8079-8089. [PMID: 30085309 PMCID: PMC6144811 DOI: 10.1093/nar/gky689] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 07/31/2018] [Indexed: 12/02/2022] Open
Abstract
Programmed –1 ribosomal frameshifting (−1PRF) is a recoding mechanism to make alternative proteins from a single mRNA transcript. −1PRF is stimulated by cis-acting signals in mRNA, a seven-nucleotide slippery sequence and a downstream secondary structure element, which is often a pseudoknot. In this study we engineered the frameshifting pseudoknot from the mouse mammary tumor virus to respond to a rationally designed small molecule naphthyridine carbamate tetramer (NCTn). We demonstrate that NCTn can stabilize the pseudoknot structure in mRNA and activate –1PRF both in vitro and in human cells. The results illustrate how NCTn-inducible –1PRF may serve as an important component of the synthetic biology toolbox for the precise control of gene expression using small synthetic molecules.
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Affiliation(s)
- Saki Matsumoto
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research (ISIR), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Neva Caliskan
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research, Josef-Schneider-Str.2/D15, 97080, Würzburg, Germany
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Asako Murata
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research (ISIR), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Kazuhiko Nakatani
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research (ISIR), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
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33
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Yokobayashi Y. Aptamer-based and aptazyme-based riboswitches in mammalian cells. Curr Opin Chem Biol 2019; 52:72-78. [PMID: 31238268 PMCID: PMC7108311 DOI: 10.1016/j.cbpa.2019.05.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 11/22/2022]
Abstract
Molecular recognition by RNA aptamers has been exploited to control gene expression in response to small molecules in mammalian cells. These mammalian synthetic riboswitches offer attractive features such as small genetic size and lower risk of immunological complications compared to protein-based transcriptional gene switches. The diversity of gene regulatory mechanisms that involve RNA has also inspired the development of mammalian riboswitches that harness various regulatory mechanisms. In this report, recent advances in synthetic riboswitches that function in mammalian cells are reviewed focusing on the regulatory mechanisms they exploit such as mRNA degradation, microRNA processing, and programmed ribosomal frameshifting.
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Affiliation(s)
- Yohei Yokobayashi
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904 0495, Japan.
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34
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Dwidar M, Yokobayashi Y. Riboswitch Signal Amplification by Controlling Plasmid Copy Number. ACS Synth Biol 2019; 8:245-250. [PMID: 30682247 DOI: 10.1021/acssynbio.8b00454] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Riboswitches are cis-acting RNA devices in mRNAs that control gene expression in response to chemical inputs. As RNA aptamers that recognize diverse classes of molecules can be isolated by in vitro selection, synthetic riboswitches hold promise for various applications in synthetic biology. One of the major drawbacks of riboswitches, however, is their limited dynamic range. A high level of gene expression in the OFF state (leakage) is also a common problem. To address these challenges, we designed and constructed a dual-riboswitch plasmid in which two genes are controlled by theophylline-activated riboswitches. One riboswitch controls the gene of interest, and another riboswitch controls RepL, a phage-derived replication protein that regulates the plasmid copy number. This single-plasmid system afforded an ON/OFF ratio as high as 3900. Furthermore, we used the system to control CRISPR interference (CRISPRi) targeting endogenous genes, and successfully observed expected phenotypic changes in Escherichia coli.
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Affiliation(s)
- Mohammed Dwidar
- 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
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35
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You M, Litke JL, Wu R, Jaffrey SR. Detection of Low-Abundance Metabolites in Live Cells Using an RNA Integrator. Cell Chem Biol 2019; 26:471-481.e3. [PMID: 30773480 DOI: 10.1016/j.chembiol.2019.01.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 12/05/2018] [Accepted: 01/10/2019] [Indexed: 01/05/2023]
Abstract
Genetically encoded biosensors are useful tools for detecting the presence and levels of diverse biomolecules in living cells. However, low-abundance targets are difficult to detect because they are often unable to bind and activate enough biosensors to detect using standard microscopic imaging approaches. Here we describe a type of RNA-based biosensor, an RNA integrator, which enables detection of low-abundance targets in vitro and in living cells. The RNA integrator is an RNA sequence comprising a ribozyme and an unfolded form of the fluorogenic aptamer Broccoli. Upon binding its target, the ribozyme undergoes cleavage and releases Broccoli, which subsequently folds and becomes fluorescent. Importantly, each target molecule can bind and induce cleavage of multiple copies of the integrator sensor, resulting in an amplified signal. We show that this approach can be generalized to numerous different ribozyme types for the detection of various small molecules.
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Affiliation(s)
- Mingxu You
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA; Department of Pharmacology, Weill Medical College, Weill Cornell Medicine, New York, NY 10065, USA.
| | - Jacob L Litke
- Department of Pharmacology, Weill Medical College, Weill Cornell Medicine, New York, NY 10065, USA
| | - Rigumula Wu
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Samie R Jaffrey
- Department of Pharmacology, Weill Medical College, Weill Cornell Medicine, New York, NY 10065, USA.
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36
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Abstract
RNA is a versatile biomolecule capable of transferring information, taking on distinct three-dimensional shapes, and reacting to ambient conditions. RNA molecules utilize a wide range of mechanisms to control gene expression. An example of such regulation is riboswitches. Consisting exclusively of RNA, they are able to control important metabolic processes, thus providing an elegant and efficient RNA-only regulation system. Existing across all domains of life, riboswitches appear to represent one of the most highly conserved mechanisms for the regulation of a broad range of biochemical pathways. Through binding of a wide range of small-molecule ligands to their so-called aptamer domain, riboswitches undergo a conformational change in their downstream "expression platform." In consequence, the pattern of gene expression changes, which in turn results in increased or decreased protein production. Riboswitches unite the sensing and transduction of a signal that can directly be coupled to the metabolism of the cell; thus they constitute a very potent regulatory mechanism for many organisms. Highly specific RNA-binding domains not only occur in vivo but can also be evolved by means of the SELEX (systematic evolution of ligands by exponential enrichment) method, which allows in vitro selection of aptamers against almost any ligand. Coupling of these aptamers with an expression platform has led to the development of synthetic riboswitches, a highly active research field of great relevance and immense potential. The aim of this review is to summarize developments in the riboswitch field over the last decade and address key questions of recent research.
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37
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Stifel J, Spöring M, Hartig JS. Expanding the toolbox of synthetic riboswitches with guanine-dependent aptazymes. Synth Biol (Oxf) 2019; 4:ysy022. [PMID: 32995528 PMCID: PMC7445771 DOI: 10.1093/synbio/ysy022] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/04/2018] [Accepted: 12/06/2018] [Indexed: 12/18/2022] Open
Abstract
Artificial riboswitches based on ribozymes serve as versatile tools for ligand-dependent gene expression regulation. Advantages of these so-called aptazymes are their modular architecture and the comparably little coding space they require. A variety of aptamer-ribozyme combinations were constructed in the past 20 years and the resulting aptazymes were applied in diverse contexts in prokaryotic and eukaryotic systems. Most in vivo functional aptazymes are OFF-switches, while ON-switches are more advantageous regarding potential applications in e.g. gene therapy vectors. We developed new ON-switching aptazymes in the model organism Escherichia coli and in mammalian cell culture using the intensely studied guanine-sensing xpt aptamer. Utilizing a high-throughput screening based on fluorescence-activated cell sorting in bacteria we identified up to 9.2-fold ON-switches and OFF-switches with a dynamic range up to 32.7-fold. For constructing ON-switches in HeLa cells, we used a rational design approach based on existing tetracycline-sensitive ON-switches. We discovered that communication modules responding to tetracycline are also functional in the context of guanine aptazymes, demonstrating a high degree of modularity. Here, guanine-responsive ON-switches with a four-fold dynamic range were designed. Summarizing, we introduce a series of novel guanine-dependent ribozyme switches operative in bacteria and human cell culture that significantly broaden the existing toolbox.
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Affiliation(s)
- Julia Stifel
- Department of Chemistry, University of Konstanz, Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Konstanz, Germany
| | - Maike Spöring
- Department of Chemistry, University of Konstanz, Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Konstanz, Germany
| | - Jörg Steffen Hartig
- Department of Chemistry, University of Konstanz, Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Konstanz, Germany
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38
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Neomycin-dependent hammerhead ribozymes for the direct control of gene expression in Saccharomyces cerevisiae. Methods 2019; 161:35-40. [PMID: 30639182 DOI: 10.1016/j.ymeth.2019.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/03/2019] [Accepted: 01/05/2019] [Indexed: 01/29/2023] Open
Abstract
Hammerhead ribozyme-based RNA switches have been proven to be powerful tools for conditional gene regulation in various organisms. We present neomycin-dependent hammerhead ribozymes (HHR) that influence gene expression in a ligand- and dose-dependent manner in S. cerevisiae. We utilized a novel design of fusing the aptamer domain to the HHR enabling for the first time the identification of genetic ON- and OFF-switches within the same library. For this purpose a neomycin aptamer was fused to stem 1 of a type 3 hammerhead ribozyme via an addressable three-way junction that shows high flexibility at the connection site. An in vivo screening approach identified sequences that allow to induce or repress gene expression 2- to 3-fold in response to neomycin addition. The ribozyme switches operate at neomycin concentrations that show no toxic effect on cell growth and pose powerful genetic tools to study and modulate cellular function in yeast.
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39
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Duperret EK, Trautz A, Stoltz R, Patel A, Wise MC, Perales-Puchalt A, Smith T, Broderick KE, Masteller E, Kim J, Humeau L, Muthumani K, Weiner DB. Synthetic DNA-Encoded Monoclonal Antibody Delivery of Anti-CTLA-4 Antibodies Induces Tumor Shrinkage In Vivo. Cancer Res 2018; 78:6363-6370. [PMID: 30287678 PMCID: PMC6239932 DOI: 10.1158/0008-5472.can-18-1429] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/16/2018] [Accepted: 09/17/2018] [Indexed: 01/07/2023]
Abstract
Antibody-based immune therapies targeting the T-cell checkpoint molecules CTLA-4 and PD-1 have affected cancer therapy. However, this immune therapy requires complex manufacturing and frequent dosing, limiting the global use of this treatment. Here, we focused on the development of a DNA-encoded monoclonal antibody (DMAb) approach for delivery of anti-CTLA-4 monoclonal antibodies in vivo With this technology, engineered and formulated DMAb plasmids encoding IgG inserts were directly injected into muscle and delivered intracellularly by electroporation, leading to in vivo expression and secretion of the encoded IgG. DMAb expression from a single dose can continue for several months without the need for repeated administration. Delivery of an optimized DMAb encoding anti-mouse CTLA-4 IgG resulted in high serum levels of the antibody as well as tumor regression in Sa1N and CT26 tumor models. DNA-delivery of the anti-human CTLA-4 antibodies ipilimumab and tremelimumab in mice achieved potent peak levels of approximately 85 and 58 μg/mL, respectively. These DMAb exhibited prolonged expression, with maintenance of serum levels at or above 15 μg/mL for over a year. Anti-human CTLA-4 DMAbs produced in vivo bound to human CTLA-4 protein expressed on stimulated human peripheral blood mononuclear cells and induced T-cell activation in a functional assay ex vivo In summary, direct in vivo expression of DMAb encoding checkpoint inhibitors serves as a novel tool for immunotherapy that could significantly improve availability and provide broader access to such therapies.Significance: DNA-encoded monoclonal antibodies represent a novel technology for delivery and expression of immune checkpoint blockade antibodies, thus expanding patient access to, and possible clinical applications of, these therapies. Cancer Res; 78(22); 6363-70. ©2018 AACR.
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Affiliation(s)
| | - Aspen Trautz
- The Wistar Institute, Vaccine & Immunotherapy Center, Philadelphia PA
| | - Regina Stoltz
- The Wistar Institute, Vaccine & Immunotherapy Center, Philadelphia PA
| | - Ami Patel
- The Wistar Institute, Vaccine & Immunotherapy Center, Philadelphia PA
| | | | | | | | | | | | | | | | - Kar Muthumani
- The Wistar Institute, Vaccine & Immunotherapy Center, Philadelphia PA
| | - David B. Weiner
- The Wistar Institute, Vaccine & Immunotherapy Center, Philadelphia PA,Corresponding author: David B. Weiner, Vaccine & Immunotherapy Center, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104,
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40
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Development of an inducible anti-VEGF rAAV gene therapy strategy for the treatment of wet AMD. Sci Rep 2018; 8:11763. [PMID: 30082848 PMCID: PMC6079038 DOI: 10.1038/s41598-018-29726-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/16/2018] [Indexed: 12/15/2022] Open
Abstract
Vascular endothelial growth factor (VEGF) is a key mediator in the development and progression of choroidal neovascularization (CNV) in patients with wet age-related macular degeneration (AMD). As a consequence, current treatment strategies typically focus on the administration of anti-VEGF agents, such as Aflibercept (Eylea), that inhibit VEGF function. While this approach is largely successful at counteracting CNV progression, the treatment can require repetitive (i.e. monthly) intravitreal injections of the anti-VEGF agent throughout the patient’s lifetime, imposing a substantial financial and medical burden on the patient. Moreover, repetitive injection of anti-VEGF agents over a period of years may encourage progression of retinal and choroidal atrophy in patients with AMD, leading to a decrease in visual acuity. Herein, we have developed a single-injection recombinant adeno-associated virus (rAAV)-based gene therapy treatment for wet AMD that prevents CNV formation through inducible over-expression of Eylea. First, we demonstrate that by incorporating riboswitch elements into the rAAV expression cassette allows protein expression levels to be modulated in vivo through oral supplementation on an activating ligand (e.g. tetracycline). We subsequently utilized this technology to modulate the intraocular concentration of Eylea following rAAV delivery, leading to nearly complete (p = 0.0008) inhibition of clinically significant CNV lesions in an established mouse model of wet AMD. The results shown in this study pave the way for the development of a personalized gene therapy strategy for the treatment of wet AMD that is substantially less invasive and more clinically adaptable than the current treatment paradigm of repetitive bolus injections of anti-VEGF agents.
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41
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Tuck AC, Natarajan KN, Rice GM, Borawski J, Mohn F, Rankova A, Flemr M, Wenger A, Nutiu R, Teichmann S, Bühler M. Distinctive features of lincRNA gene expression suggest widespread RNA-independent functions. Life Sci Alliance 2018; 1:e201800124. [PMID: 30456373 PMCID: PMC6238598 DOI: 10.26508/lsa.201800124] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 07/13/2018] [Accepted: 07/13/2018] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic genomes produce RNAs lacking protein-coding potential, with enigmatic roles. We integrated three approaches to study large intervening noncoding RNA (lincRNA) gene functions. First, we profiled mouse embryonic stem cells and neural precursor cells at single-cell resolution, revealing lincRNAs expressed in specific cell types, cell subpopulations, or cell cycle stages. Second, we assembled a transcriptome-wide atlas of nuclear lincRNA degradation by identifying targets of the exosome cofactor Mtr4. Third, we developed a reversible depletion system to separate the role of a lincRNA gene from that of its RNA. Our approach distinguished lincRNA loci functioning in trans from those modulating local gene expression. Some genes express stable and/or abundant lincRNAs in single cells, but many prematurely terminate transcription and produce lincRNAs rapidly degraded by the nuclear exosome. This suggests that besides RNA-dependent functions, lincRNA loci act as DNA elements or through transcription. Our integrative approach helps distinguish these mechanisms.
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Affiliation(s)
- Alex C Tuck
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Kedar Nath Natarajan
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.,Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.,Danish Institute of Advanced Study and Functional Genomics and Metabolism Unit, University of Southern Denmark, Denmark
| | - Greggory M Rice
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Jason Borawski
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Fabio Mohn
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Aneliya Rankova
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Matyas Flemr
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Alice Wenger
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Razvan Nutiu
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Sarah Teichmann
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.,Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Marc Bühler
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
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42
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Kobori S, Yokobayashi Y. Analyzing and Tuning Ribozyme Activity by Deep Sequencing To Modulate Gene Expression Level in Mammalian Cells. ACS Synth Biol 2018; 7:371-376. [PMID: 29343061 DOI: 10.1021/acssynbio.7b00367] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Self-cleaving ribozymes, in combination with aptamers and various classes of RNAs, have been heavily engineered to create RNA devices to control gene expression. Although understanding of sequence-function relationships of ribozymes is critical for such efforts, our current knowledge of self-cleaving ribozymes is mostly limited to the results from small scale mutational studies performed under different conditions, or qualitative results of mutate-and-select experiments that may contain experimental biases. Here, we applied our strategy based on deep sequencing to comprehensively assay a large number of mutants to systematically examine the effect of the P4 stem sequence on the activity of an HDV-like ribozyme. We discovered that the ribozyme activity is highly sensitive to the sequence and the apparent stability of the varied positions. Furthermore, we demonstrated that the collection of the ribozyme variants with different activities can be used as a convenient device to fine-tune the level of gene expression in mammalian cells.
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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
| | - Yohei Yokobayashi
- Nucleic Acid Chemistry and
Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904 0495, Japan
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43
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Dhamodharan V, Nomura Y, Dwidar M, Yokobayashi Y. Optochemical control of gene expression by photocaged guanine and riboswitches. Chem Commun (Camb) 2018; 54:6181-6183. [DOI: 10.1039/c8cc02290a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A photocaged guanine was synthesized to optically control gene expression in cells using synthetic riboswitches.
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Affiliation(s)
- V. Dhamodharan
- Nucleic Acid Chemistry and Engineering Unit
- Okinawa Institute of Science and Technology Graduate University
- Onna
- Okinawa
- Japan
| | - Yoko Nomura
- Nucleic Acid Chemistry and Engineering Unit
- Okinawa Institute of Science and Technology Graduate University
- Onna
- Okinawa
- Japan
| | - Mohammed Dwidar
- Nucleic Acid Chemistry and Engineering Unit
- Okinawa Institute of Science and Technology Graduate University
- Onna
- Okinawa
- Japan
| | - Yohei Yokobayashi
- Nucleic Acid Chemistry and Engineering Unit
- Okinawa Institute of Science and Technology Graduate University
- Onna
- Okinawa
- Japan
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44
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Wurmthaler LA, Klauser B, Hartig JS. Highly motif- and organism-dependent effects of naturally occurring hammerhead ribozyme sequences on gene expression. RNA Biol 2017; 15:231-241. [PMID: 29106331 DOI: 10.1080/15476286.2017.1397870] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Recent bioinformatics studies have demonstrated a wide-spread occurrence of the hammerhead ribozyme (HHR) and similar small endonucleolytic RNA motifs in all domains of life. It is becoming increasingly evident that such ribozyme motifs participate in important genetic processes in diverse organisms. Although the HHR motif has been studied for more than three decades, only little is known about the consequences of ribozyme activity on gene expression. In the present study we analysed eight different naturally occurring HHR sequences in diverse genetic and organismal contexts. We investigated the influence of active ribozymes incorporated into mRNAs in mammalian, yeast and bacterial expression systems. The experiments show an unexpectedly high degree of organism-specific variability of ribozyme-mediated effects on gene expression. The presented findings demonstrate that ribozyme cleavage profoundly affect gene expression. However, the extent of this effect varies and depends strongly on the respective genetic context. The fast-cleaving type 3 HHRs [CChMVd(-) and sLTSV(-)] generally tended to cause the strongest effects on intracellular gene expression. The presented results are important in order to address potential functions of naturally occurring ribozymes in RNA processing and post-transcriptional regulation of gene expression. Additionally, our results are of interest for biotechnology and synthetic biology approaches that aim at the utilisation of self-cleaving ribozymes as widely applicable tools for controlling genetic processes.
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Affiliation(s)
- Lena A Wurmthaler
- a Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB) , University of Konstanz , Konstanz , Germany
| | - Benedikt Klauser
- a Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB) , University of Konstanz , Konstanz , Germany
| | - Jörg S Hartig
- a Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB) , University of Konstanz , Konstanz , Germany
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45
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Kim CM, Smolke CD. Biomedical applications of RNA-based devices. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2017; 4:106-115. [DOI: 10.1016/j.cobme.2017.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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46
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Ausländer S, Fussenegger M. Synthetic RNA-based switches for mammalian gene expression control. Curr Opin Biotechnol 2017; 48:54-60. [DOI: 10.1016/j.copbio.2017.03.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/10/2017] [Indexed: 01/25/2023]
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47
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Jang S, Jang S, Yang J, Seo SW, Jung GY. RNA-based dynamic genetic controllers: development strategies and applications. Curr Opin Biotechnol 2017; 53:1-11. [PMID: 29132120 PMCID: PMC7126020 DOI: 10.1016/j.copbio.2017.10.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/11/2017] [Accepted: 10/16/2017] [Indexed: 12/25/2022]
Abstract
Unique properties of RNA lead to the development of RNA-based dynamic genetic controllers. Natural riboswitches are re-engineered to detect new molecules. RNA-based regulatory mechanisms are exploited to construct novel dynamic RNA controllers. Computational methods and in vitro–in vivo selection enable de novo design of dynamic RNA controllers. Dynamic RNA controllers are utilized for metabolic engineering and synthetic biology.
Dynamic regulation of gene expression in response to various molecules is crucial for both basic science and practical applications. RNA is considered an attractive material for creating dynamic genetic controllers because of its specific binding to ligands, structural flexibility, programmability, and small size. Here, we review recent advances in strategies for developing RNA-based dynamic controllers and applications. First, we describe studies that re-engineered natural riboswitches to generate new dynamic controllers. Next, we summarize RNA-based regulatory mechanisms that have been exploited to build novel artificial dynamic controllers. We also discuss computational methods and high-throughput selection approaches for de novo design of dynamic RNA controllers. Finally, we explain applications of dynamic RNA controllers for metabolic engineering and synthetic biology.
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Affiliation(s)
- Sungho Jang
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Sungyeon Jang
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Jina Yang
- School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, 1, Gwanak-ro, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Sang Woo Seo
- School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, 1, Gwanak-ro, Gwanak-Gu, Seoul 08826, Republic of Korea.
| | - Gyoo Yeol Jung
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Republic of Korea; School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Republic of Korea.
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48
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Findeiß S, Etzel M, Will S, Mörl M, Stadler PF. Design of Artificial Riboswitches as Biosensors. SENSORS 2017; 17:s17091990. [PMID: 28867802 PMCID: PMC5621056 DOI: 10.3390/s17091990] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 08/23/2017] [Accepted: 08/25/2017] [Indexed: 12/11/2022]
Abstract
RNA aptamers readily recognize small organic molecules, polypeptides, as well as other nucleic acids in a highly specific manner. Many such aptamers have evolved as parts of regulatory systems in nature. Experimental selection techniques such as SELEX have been very successful in finding artificial aptamers for a wide variety of natural and synthetic ligands. Changes in structure and/or stability of aptamers upon ligand binding can propagate through larger RNA constructs and cause specific structural changes at distal positions. In turn, these may affect transcription, translation, splicing, or binding events. The RNA secondary structure model realistically describes both thermodynamic and kinetic aspects of RNA structure formation and refolding at a single, consistent level of modelling. Thus, this framework allows studying the function of natural riboswitches in silico. Moreover, it enables rationally designing artificial switches, combining essentially arbitrary sensors with a broad choice of read-out systems. Eventually, this approach sets the stage for constructing versatile biosensors.
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Affiliation(s)
- Sven Findeiß
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, University Leipzig, Härtelstraße 16-18, 04107 Leipzig, Germany.
- Faculty of Computer Science, Research Group Bioinformatics and Computational Biology, University of Vienna, Währingerstraße 29, A-1090 Vienna, Austria.
- Faculty of Chemistry, Department of Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Vienna, Austria.
| | - Maja Etzel
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany.
| | - Sebastian Will
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, University Leipzig, Härtelstraße 16-18, 04107 Leipzig, Germany.
- Faculty of Chemistry, Department of Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Vienna, Austria.
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany.
| | - Mario Mörl
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany.
| | - Peter F Stadler
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, University Leipzig, Härtelstraße 16-18, 04107 Leipzig, Germany.
- Faculty of Chemistry, Department of Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Vienna, Austria.
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany.
- Max Planck Institute for Mathematics in the Sciences, Inselstraße 22, 04103 Leipzig, Germany.
- Fraunhofer Institute for Cell Therapy and Immunology, Perlickstrasse 1, 04103 Leipzig, Germany.
- Center for RNA in Technology and Health, University of Copenhagen, Grønnegårdsvej 3, 1870 Frederiksberg , Denmark.
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA.
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Domin G, Findeiß S, Wachsmuth M, Will S, Stadler PF, Mörl M. Applicability of a computational design approach for synthetic riboswitches. Nucleic Acids Res 2017; 45:4108-4119. [PMID: 27994029 PMCID: PMC5397205 DOI: 10.1093/nar/gkw1267] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 12/06/2016] [Indexed: 02/07/2023] Open
Abstract
Riboswitches have gained attention as tools for synthetic biology, since they enable researchers to reprogram cells to sense and respond to exogenous molecules. In vitro evolutionary approaches produced numerous RNA aptamers that bind such small ligands, but their conversion into functional riboswitches remains difficult. We previously developed a computational approach for the design of synthetic theophylline riboswitches based on secondary structure prediction. These riboswitches have been constructed to regulate ligand-dependent transcription termination in Escherichia coli. Here, we test the usability of this design strategy by applying the approach to tetracycline and streptomycin aptamers. The resulting tetracycline riboswitches exhibit robust regulatory properties in vivo. Tandem fusions of these riboswitches with theophylline riboswitches represent logic gates responding to two different input signals. In contrast, the conversion of the streptomycin aptamer into functional riboswitches appears to be difficult. Investigations of the underlying aptamer secondary structure revealed differences between in silico prediction and structure probing. We conclude that only aptamers adopting the minimal free energy (MFE) structure are suitable targets for construction of synthetic riboswitches with design approaches based on equilibrium thermodynamics of RNA structures. Further improvements in the design strategy are required to implement aptamer structures not corresponding to the calculated MFE state.
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Affiliation(s)
- Gesine Domin
- Leipzig University, Institute for Biochemistry, 04103 Leipzig, Germany
| | - Sven Findeiß
- University of Vienna, Research Group Bioinformatics and Computational Biology, Faculty of Computer Science, A-1090 Vienna, Austria.,University of Vienna, Institute for Theoretical Chemistry, A-1090 Vienna, Austria
| | - Manja Wachsmuth
- Leipzig University, Institute for Biochemistry, 04103 Leipzig, Germany
| | - Sebastian Will
- Leipzig University, Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, 04107 Leipzig, Germany
| | - Peter F Stadler
- University of Vienna, Institute for Theoretical Chemistry, A-1090 Vienna, Austria.,Leipzig University, Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, 04107 Leipzig, Germany.,Max Planck Institute for Mathematics in the Science, 04103 Leipzig, Germany.,Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany.,Santa Fe Institute, Santa Fe NM 87501, USA
| | - Mario Mörl
- Leipzig University, Institute for Biochemistry, 04103 Leipzig, Germany
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50
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Cheng H, Zhang Y, Wang H, Sun N, Liu M, Chen H, Pei R. Regulation of MAP4K4 gene expression by RNA interference through an engineered theophylline-dependent hepatitis delta virus ribozyme switch. MOLECULAR BIOSYSTEMS 2017; 12:3370-3376. [PMID: 27754501 DOI: 10.1039/c6mb00540c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Riboswitches are functional non-coding RNA regulatory components that play an important role in the regulation of gene expression in diverse organisms. In particular, using riboswitches to modulate RNA interference (RNAi) enables temporal and spatial control of gene expression in mammalian cells. Herein, a ribozyme gene switch to activate RNAi was fabricated for the artificial regulation of versatile gene silencing through the interaction of an RNA aptamer with small molecules. The device comprised an allosteric HDV ribozyme with an embedded theophylline aptamer and a primary miRNA (pri-miRNA) to silence the MAP4K4 gene in hepatic (HepG2) cells, aiming to achieve dose-dependent control of the activation of RNAi, and then the regulation of the MAP4K4 gene by theophylline. Finally, we demonstrated the feasibility and applicability of utilizing HDV ribozyme switches to activate RNAi for regulating an endogenous gene in mammalian cells.
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Affiliation(s)
- Hui Cheng
- College of Life Sciences, Shanghai University, Shanghai 200444, China and Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Yuanyuan Zhang
- Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Hongyan Wang
- College of Life Sciences, Shanghai University, Shanghai 200444, China and Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Na Sun
- Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Min Liu
- Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Hongxia Chen
- College of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Renjun Pei
- Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
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