1
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Weber F, Motzkus NA, Brandl L, Möhler M, Alempijevic A, Jäschke A. Identification and in vitro characterization of UDP-GlcNAc-RNA cap-modifying and decapping enzymes. Nucleic Acids Res 2024; 52:5438-5450. [PMID: 38716860 PMCID: PMC11162767 DOI: 10.1093/nar/gkae353] [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: 06/13/2023] [Revised: 04/09/2024] [Accepted: 04/22/2024] [Indexed: 06/11/2024] Open
Abstract
In recent years, several noncanonical RNA caps derived from cofactors and metabolites have been identified. Purine-containing RNA caps have been extensively studied, with multiple decapping enzymes identified and efficient capture and sequencing protocols developed for nicotinamide adenine dinucleotide (NAD)-RNA, which allowed for a stepwise elucidation of capping functions. Despite being identified as an abundant noncanonical RNA-cap, UDP-sugar-capped RNA remains poorly understood, which is partly due to its complex in vitro preparation. Here, we describe a scalable synthesis of sugar-capped uridine-guanosine dinucleotides from readily available protected building blocks and their enzymatic conversion into several cell wall precursor-capped dinucleotides. We employed these capped dinucleotides in T7 RNA polymerase-catalyzed in vitro transcription reactions to efficiently generate RNAs capped with uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), its N-azidoacetyl derivative UDP-GlcNAz, and various cell wall precursors. We furthermore identified four enzymes capable of processing UDP-GlcNAc-capped RNA in vitro: MurA, MurB and MurC from Escherichia coli can sequentially modify the sugar-cap structure and were used to introduce a bioorthogonal, clickable moiety, and the human Nudix hydrolase Nudt5 was shown to efficiently decap UDP-GlcNAc-RNA. Our findings underscore the importance of efficient synthetic methods for capped model RNAs. Additionally, we provide useful enzymatic tools that could be utilized in the development and application of UDP-GlcNAc capture and sequencing protocols. Such protocols are essential for deepening our understanding of the widespread yet enigmatic GlcNAc modification of RNA and its physiological significance.
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Affiliation(s)
- Frederik Weber
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, Heidelberg 69120, Germany
| | - Nikolas Alexander Motzkus
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, Heidelberg 69120, Germany
| | - Leona Brandl
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, Heidelberg 69120, Germany
| | - Marvin Möhler
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, Heidelberg 69120, Germany
| | - Andrijana Alempijevic
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, Heidelberg 69120, Germany
| | - Andres Jäschke
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, Heidelberg 69120, Germany
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2
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Li J, Kang X, Guidi I, Lu L, Fernández-Millán P, Prats-Ejarque G, Boix E. Structural determinants for tRNA selective cleavage by RNase 2/EDN. Structure 2024; 32:328-341.e4. [PMID: 38228145 DOI: 10.1016/j.str.2023.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/03/2023] [Accepted: 12/20/2023] [Indexed: 01/18/2024]
Abstract
tRNA-derived fragments (tRFs) have emerged as key players of immunoregulation. Some RNase A superfamily members participate in the shaping of the tRFs population. By comparing wild-type and knockout macrophage cell lines, our previous work revealed that RNase 2 can selectively cleave tRNAs. Here, we confirm the in vitro protein cleavage pattern by screening of synthetic tRNAs, single-mutant variants, and anticodon-loop DNA/RNA hairpins. By sequencing of tRF products, we identified the cleavage selectivity of recombinant RNase 2 with base specificity at B1 (U/C) and B2 (A) sites, consistent with a previous cellular study. Lastly, protein-hairpin complexes were predicted by MD simulations. Results reveal the contribution of the α1, loop 3 and loop 4, and β6 RNase 2 regions, where residues Arg36/Asn39/Gln40/Asn65/Arg68/Arg132 provide interactions, spanning from P-1 to P2 sites that are essential for anticodon loop recognition. Knowledge of RNase 2-specific tRFs generation might guide new therapeutic approaches for infectious and immune-related diseases.
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Affiliation(s)
- Jiarui Li
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193 Barcelona, Spain.
| | - Xincheng Kang
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193 Barcelona, Spain
| | - Irene Guidi
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193 Barcelona, Spain
| | - Lu Lu
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193 Barcelona, Spain
| | - Pablo Fernández-Millán
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193 Barcelona, Spain
| | - Guillem Prats-Ejarque
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193 Barcelona, Spain
| | - Ester Boix
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193 Barcelona, Spain.
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3
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Lobodin KV, Chetverina HV, Chetverin AB. Slippage at the initiation of RNA synthesis by Qβ replicase results in a periodic polyG pattern. FEBS Lett 2023; 597:458-471. [PMID: 36477752 DOI: 10.1002/1873-3468.14556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 10/16/2022] [Accepted: 11/25/2022] [Indexed: 12/13/2022]
Abstract
The repetitive copying of template nucleotides due to transcriptional slippage has not been reported for RNA-directed RNA polymerases of positive-strand RNA phages. We unexpectedly observed that, with GTP as the only substrate, Qβ replicase, the RNA-directed RNA polymerase of bacteriophage Qβ, synthesizes by transcriptional slippage polyG strands, which on denaturing electrophoresis produce a ladder with at least three clusters of bolder bands. The ≈ 15-nt-long G15 , the major product of the shortest cluster, is tightly bound by the enzyme but can be released by the ribosomal protein S1, which, as a Qβ replicase subunit, normally promotes the release of a completed transcript. 7-deaza-GTP suppresses the polyG synthesis and abolishes the periodic pattern, suggesting that the N7 atom is needed for the initiation of RNA synthesis and the formation of the structure recognized by protein S1. The results provide new insights into the mechanism of RNA synthesis by the RNA-directed RNA polymerase of a single-stranded RNA phage.
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Affiliation(s)
- Kirill V Lobodin
- Institute of Protein Research of the Russian Academy of Sciences, Pushchino, Russia
| | - Helena V Chetverina
- Institute of Protein Research of the Russian Academy of Sciences, Pushchino, Russia
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4
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Cai H, Roca J, Zhao YF, Woodson SA. Dynamic Refolding of OxyS sRNA by the Hfq RNA Chaperone. J Mol Biol 2022; 434:167776. [PMID: 35934049 PMCID: PMC10044511 DOI: 10.1016/j.jmb.2022.167776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 07/19/2022] [Accepted: 08/01/2022] [Indexed: 10/16/2022]
Abstract
The Sm protein Hfq chaperones small non-coding RNAs (sRNAs) in bacteria, facilitating sRNA regulation of target mRNAs. Hfq acts in part by remodeling the sRNA and mRNA structures, yet the basis for this remodeling activity is not understood. To understand how Hfq remodels RNA, we used single-molecule Förster resonance energy transfer (smFRET) to monitor conformational changes in OxyS sRNA upon Hfq binding. The results show that E. coli Hfq first compacts OxyS, bringing its 5' and 3 ends together. Next, Hfq destabilizes an internal stem-loop in OxyS, allowing the RNA to adopt a more open conformation that is stabilized by a conserved arginine on the rim of Hfq. The frequency of transitions between compact and open conformations depend on interactions with Hfqs flexible C-terminal domain (CTD), being more rapid when the CTD is deleted, and slower when OxyS is bound to Caulobacter crescentus Hfq, which has a shorter and more stable CTD than E. coli Hfq. We propose that the CTDs gate transitions between OxyS conformations that are stabilized by interaction with one or more arginines. These results suggest a general model for how basic residues and intrinsically disordered regions of RNA chaperones act together to refold RNA.
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Affiliation(s)
- Huahuan Cai
- Department of Biophysics, Johns Hopkins University, 3400 N. Charles St., MD 21218, USA; Department of Chemistry, College of Chemistry and Chemical Engineering, and Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, Fujian 361005, China
| | - Jorjethe Roca
- Department of Biophysics, Johns Hopkins University, 3400 N. Charles St., MD 21218, USA
| | - Yu-Fen Zhao
- Department of Chemistry, College of Chemistry and Chemical Engineering, and Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, Fujian 361005, China; Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Sarah A Woodson
- Department of Biophysics, Johns Hopkins University, 3400 N. Charles St., MD 21218, USA.
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5
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Sinha T, Yazdani SS. Genome editing in Penicillium funiculosum using in vitro assembled CRISPR-Cas9 ribonucleoprotein complexes. STAR Protoc 2022; 3:101629. [PMID: 36042883 PMCID: PMC9420531 DOI: 10.1016/j.xpro.2022.101629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The plasmid-free CRISPR-Cas9-based genome editing in fungi is a precise and time-saving approach. Here, we present a detailed protocol for genetic manipulation in Penicillium funiculosum, which includes design and synthesis of sgRNA, high-quality protoplast preparation, and PEG-mediated protoplast transformation of linear donor DNA along with in vitro synthesized RNP complex composed of sgRNA and host-specific Cas9. This technique is beneficial for researchers interested in functional analysis of genes as it improves reproducibility and replicability of the experiment. For complete details on the use and execution of this protocol, please refer to Randhawa et al. (2021). Development of high-quality protoplasts allows the uptake of donor DNA and RNP complex In vitro assembled RNP complex enables rapid knockout generation Cas9 possessing host-specific NLS boosts the reproducibility of the experiment
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
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Affiliation(s)
- Tulika Sinha
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Syed Shams Yazdani
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India; DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India.
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6
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Feyrer H, Gurdap CO, Marušič M, Schlagnitweit J, Petzold K. Enzymatic incorporation of an isotope-labeled adenine into RNA for the study of conformational dynamics by NMR. PLoS One 2022; 17:e0264662. [PMID: 35802676 PMCID: PMC9269771 DOI: 10.1371/journal.pone.0264662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 06/08/2022] [Indexed: 11/28/2022] Open
Abstract
Solution NMR spectroscopy is a well-established tool with unique advantages for structural studies of RNA molecules. However, for large RNA sequences, the NMR resonances often overlap severely. A reliable way to perform resonance assignment and allow further analysis despite spectral crowding is the use of site-specific isotope labeling in sample preparation. While solid-phase oligonucleotide synthesis has several advantages, RNA length and availability of isotope-labeled building blocks are persistent issues. Purely enzymatic methods represent an alternative and have been presented in the literature. In this study, we report on a method in which we exploit the preference of T7 RNA polymerase for nucleotide monophosphates over triphosphates for the 5’ position, which allows 5’-labeling of RNA. Successive ligation to an unlabeled RNA strand generates a site-specifically labeled RNA. We show the successful production of such an RNA sample for NMR studies, report on experimental details and expected yields, and present the surprising finding of a previously hidden set of peaks which reveals conformational exchange in the RNA structure. This study highlights the feasibility of site-specific isotope-labeling of RNA with enzymatic methods.
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Affiliation(s)
- Hannes Feyrer
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Cenk Onur Gurdap
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Maja Marušič
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
- Slovenian NMR Center, National Institute of Chemistry, Ljubljana, Slovenia
| | - Judith Schlagnitweit
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
- Centre de RMN à Très Hauts Champs de Lyon, UMR5082 CNRS/ENS-Lyon/Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Katja Petzold
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
- * E-mail:
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7
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Saito-Tarashima N, Ueno M, Murai A, Matsuo A, Minakawa N. Cas9-mediated DNA cleavage guided by enzymatically prepared 4'-thio-modified RNA. Org Biomol Chem 2022; 20:5245-5248. [PMID: 35726625 DOI: 10.1039/d2ob00742h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
CRISPR-Cas9-mediated DNA editing relies on guide RNAs (gRNAs) that direct site-specific DNA cleavage by the Cas endonuclease. Because natural gRNA is susceptible to intracellular degradation, it is desirable to chemically protect it for efficient editing. Using 4'-thioribonucleoside 5'-triphosphates and T7 transcription, we have prepared 4'-thio-modified gRNAs that guide Cas9-mediated DNA cleavage. This approach is a simple way to obtain chemically modified RNA suitable for CRISPR-Cas9 DNA editing.
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Affiliation(s)
- Noriko Saito-Tarashima
- Graduate School of Pharmaceutical Science, Tokushima University, Shomachi 1-78-1, Tokushima, 770-8505, Japan.
| | - Mana Ueno
- Graduate School of Pharmaceutical Science, Tokushima University, Shomachi 1-78-1, Tokushima, 770-8505, Japan.
| | - Akiho Murai
- Graduate School of Pharmaceutical Science, Tokushima University, Shomachi 1-78-1, Tokushima, 770-8505, Japan.
| | - Ayako Matsuo
- Graduate School of Pharmaceutical Science, Tokushima University, Shomachi 1-78-1, Tokushima, 770-8505, Japan.
| | - Noriaki Minakawa
- Graduate School of Pharmaceutical Science, Tokushima University, Shomachi 1-78-1, Tokushima, 770-8505, Japan.
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8
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Czerniak T, Saenz JP. Lipid membranes modulate the activity of RNA through sequence-dependent interactions. Proc Natl Acad Sci U S A 2022; 119:e2119235119. [PMID: 35042820 PMCID: PMC8794826 DOI: 10.1073/pnas.2119235119] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/02/2021] [Indexed: 12/11/2022] Open
Abstract
RNA is a ubiquitous biomolecule that can serve as both catalyst and information carrier. Understanding how RNA bioactivity is controlled is crucial for elucidating its physiological roles and potential applications in synthetic biology. Here, we show that lipid membranes can act as RNA organization platforms, introducing a mechanism for riboregulation. The activity of R3C ribozyme can be modified by the presence of lipid membranes, with direct RNA-lipid interactions dependent on RNA nucleotide content, base pairing, and length. In particular, the presence of guanine in short RNAs is crucial for RNA-lipid interactions, and G-quadruplex formation further promotes lipid binding. Lastly, by artificially modifying the R3C substrate sequence to enhance membrane binding, we generated a lipid-sensitive ribozyme reaction with riboswitch-like behavior. These findings introduce RNA-lipid interactions as a tool for developing synthetic riboswitches and RNA-based lipid biosensors and bear significant implications for RNA world scenarios for the origin of life.
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Affiliation(s)
- Tomasz Czerniak
- B CUBE Center for Molecular Bioengineering, Technische Universität Dresden, 01307 Dresden, Germany
| | - James P Saenz
- B CUBE Center for Molecular Bioengineering, Technische Universität Dresden, 01307 Dresden, Germany
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9
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Yang H, Eremeeva E, Abramov M, Herdewijn P. The Network of Replication, Transcription, and Reverse Transcription of a Synthetic Genetic Cassette. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202011887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hui Yang
- Medicinal Chemistry Rega Institute for Medical Research KU Leuven Herestraat 49, Box-1041 3000 Leuven Belgium
| | - Elena Eremeeva
- Medicinal Chemistry Rega Institute for Medical Research KU Leuven Herestraat 49, Box-1041 3000 Leuven Belgium
| | - Mikhail Abramov
- Medicinal Chemistry Rega Institute for Medical Research KU Leuven Herestraat 49, Box-1041 3000 Leuven Belgium
| | - Piet Herdewijn
- Medicinal Chemistry Rega Institute for Medical Research KU Leuven Herestraat 49, Box-1041 3000 Leuven Belgium
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10
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Yang H, Eremeeva E, Abramov M, Herdewijn P. The Network of Replication, Transcription, and Reverse Transcription of a Synthetic Genetic Cassette. Angew Chem Int Ed Engl 2020; 60:4175-4182. [PMID: 33142013 DOI: 10.1002/anie.202011887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/27/2020] [Indexed: 11/07/2022]
Abstract
Synthetic nucleic acids, with four non-canonical nucleobases, can function as genetic materials. A comprehensive analysis of PCR amplification, transcription, reverse transcription, and cloning was done to screen for alternative genetic monomers. A small library of six modified nucleobases was selected: the modified 2'-deoxyribonucleoside (dZTPs) and ribonucleoside (rZTPs) triphosphates of 7-deaza-adenine, 5-chlorouracil, 7-deaza-guanine or inosine together with 5-fluorocytosine or 5-bromocytosine. The fragments composed of one to four modified nucleotides (denoted as DZA) have been successfully recognized and transcribed to natural or modified RNA (denoted as RZA) by T7 RNA polymerase. The fully modified RZA fragment could be reverse transcribed and then amplified in the presence of various dZTPs. Noticeably, modified fragments could function as genetic templates in vivo by encoding the 678 base pair gene of a fluorescent protein in bacteria. These results demonstrate the existence of a fully simulated genetic circuit that uses synthetic materials.
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Affiliation(s)
- Hui Yang
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, Box-1041, 3000, Leuven, Belgium
| | - Elena Eremeeva
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, Box-1041, 3000, Leuven, Belgium
| | - Mikhail Abramov
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, Box-1041, 3000, Leuven, Belgium
| | - Piet Herdewijn
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, Box-1041, 3000, Leuven, Belgium
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11
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Generation of recombinant rotaviruses from just 11 cDNAs encoding a viral genome. Virus Res 2020; 286:198075. [DOI: 10.1016/j.virusres.2020.198075] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/20/2020] [Accepted: 06/23/2020] [Indexed: 01/06/2023]
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12
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Karlsson H, Baronti L, Petzold K. A robust and versatile method for production and purification of large-scale RNA samples for structural biology. RNA (NEW YORK, N.Y.) 2020; 26:1023-1037. [PMID: 32354720 PMCID: PMC7373988 DOI: 10.1261/rna.075697.120] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 04/25/2020] [Indexed: 05/16/2023]
Abstract
Recent findings in genome-wide transcriptomics revealed that RNAs are involved in almost every biological process, across all domains of life. The characterization of native RNAs of unknown function and structure is particularly challenging due to their typical low abundance in the cell and the inherent sensitivity toward ubiquitous RNA degrading enzymes. Therefore, robust in vitro synthesis and extensive work-up methods are often needed to obtain samples amenable for biochemical, biophysical, and structural studies. Here, we present a protocol that combines the most recent advances in T7 in vitro transcription methodology with reverse phase ion pairing and ion exchange HPLC purification of RNAs for the production of yield-optimized large-scale samples. The method is easy to follow, robust and suitable for users with little or no experience within the field of biochemistry or chromatography. The complete execution of this method, for example, for production of isotopically labeled NMR samples, can be performed in less than a week.
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Affiliation(s)
- Hampus Karlsson
- Department of Medical Biochemistry and Biophysics (MBB), Karolinska Institutet, SE-104 35 Stockholm, Sweden
| | - Lorenzo Baronti
- Department of Medical Biochemistry and Biophysics (MBB), Karolinska Institutet, SE-104 35 Stockholm, Sweden
| | - Katja Petzold
- Department of Medical Biochemistry and Biophysics (MBB), Karolinska Institutet, SE-104 35 Stockholm, Sweden
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13
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Feyrer H, Munteanu R, Baronti L, Petzold K. One-Pot Production of RNA in High Yield and Purity Through Cleaving Tandem Transcripts. Molecules 2020; 25:E1142. [PMID: 32143353 PMCID: PMC7179201 DOI: 10.3390/molecules25051142] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/25/2020] [Accepted: 03/01/2020] [Indexed: 02/06/2023] Open
Abstract
There is an increasing demand for efficient and robust production of short RNA molecules in both pharmaceutics and research. A standard method is in vitro transcription by T7 RNA polymerase. This method is sequence-dependent on efficiency and is limited to products longer than ~12 nucleotides. Additionally, the native initiation sequence is required to achieve high yields, putting a strain on sequence variability. Deviations from this sequence can lead to side products, requiring laborious purification, further decreasing yield. We here present transcribing tandem repeats of the target RNA sequence followed by site-specific cleavage to obtain RNA in high purity and yield. This approach makes use of a plasmid DNA template and RNase H-directed cleavage of the transcript. The method is simpler and faster than previous protocols, as it can be performed as one pot synthesis and provides at the same time higher yields of RNA.
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Affiliation(s)
| | | | | | - Katja Petzold
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
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14
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Flamme M, McKenzie LK, Sarac I, Hollenstein M. Chemical methods for the modification of RNA. Methods 2019; 161:64-82. [PMID: 30905751 DOI: 10.1016/j.ymeth.2019.03.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 02/06/2023] Open
Abstract
RNA is often considered as being the vector for the transmission of genetic information from DNA to the protein synthesis machinery. However, besides translation RNA participates in a broad variety of fundamental biological roles such as gene expression and regulation, protein synthesis, and even catalysis of chemical reactions. This variety of function combined with intricate three-dimensional structures and the discovery of over 100 chemical modifications in natural RNAs require chemical methods for the modification of RNAs in order to investigate their mechanism, location, and exact biological roles. In addition, numerous RNA-based tools such as ribozymes, aptamers, or therapeutic oligonucleotides require the presence of additional chemical functionalities to strengthen the nucleosidic backbone against degradation or enhance the desired catalytic or binding properties. Herein, the two main methods for the chemical modification of RNA are presented: solid-phase synthesis using phosphoramidite precursors and the enzymatic polymerization of nucleoside triphosphates. The different synthetic and biochemical steps required for each method are carefully described and recent examples of practical applications based on these two methods are discussed.
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Affiliation(s)
- Marie Flamme
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France; Sorbonne Université, Collège doctoral, F-75005 Paris, France
| | - Luke K McKenzie
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Ivo Sarac
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Marcel Hollenstein
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France.
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15
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Milisavljevič N, Perlíková P, Pohl R, Hocek M. Enzymatic synthesis of base-modified RNA by T7 RNA polymerase. A systematic study and comparison of 5-substituted pyrimidine and 7-substituted 7-deazapurine nucleoside triphosphates as substrates. Org Biomol Chem 2019; 16:5800-5807. [PMID: 30063056 DOI: 10.1039/c8ob01498a] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We synthesized a small library of eighteen 5-substituted pyrimidine or 7-substituted 7-deazapurine nucleoside triphosphates bearing methyl, ethynyl, phenyl, benzofuryl or dibenzofuryl groups through cross-coupling reactions of nucleosides followed by triphosphorylation or through direct cross-coupling reactions of halogenated nucleoside triphosphates. We systematically studied the influence of the modification on the efficiency of T7 RNA polymerase catalyzed synthesis of modified RNA and found that modified ATP, UTP and CTP analogues bearing smaller modifications were good substrates and building blocks for the RNA synthesis even in difficult sequences incorporating multiple modified nucleotides. Bulky dibenzofuryl derivatives of ATP and GTP were not substrates for the RNA polymerase. In the case of modified GTP analogues, a modified procedure using a special promoter and GMP as initiator needed to be used to obtain efficient RNA synthesis. The T7 RNA polymerase synthesis of modified RNA can be very efficiently used for synthesis of modified RNA but the method has constraints in the sequence of the first three nucleotides of the transcript, which must contain a non-modified G in the +1 position.
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Affiliation(s)
- Nemanja Milisavljevič
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, CZ-16610, Prague 6, Czech Republic.
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16
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Pinzón N, Bertrand S, Subirana L, Busseau I, Escrivá H, Seitz H. Functional lability of RNA-dependent RNA polymerases in animals. PLoS Genet 2019; 15:e1007915. [PMID: 30779744 PMCID: PMC6396948 DOI: 10.1371/journal.pgen.1007915] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 03/01/2019] [Accepted: 12/24/2018] [Indexed: 11/18/2022] Open
Abstract
RNA interference (RNAi) requires RNA-dependent RNA polymerases (RdRPs) in many eukaryotes, and RNAi amplification constitutes the only known function for eukaryotic RdRPs. Yet in animals, classical model organisms can elicit RNAi without possessing RdRPs, and only nematode RNAi was shown to require RdRPs. Here we show that RdRP genes are much more common in animals than previously thought, even in insects, where they had been assumed not to exist. RdRP genes were present in the ancestors of numerous clades, and they were subsequently lost at a high frequency. In order to probe the function of RdRPs in a deuterostome (the cephalochordate Branchiostoma lanceolatum), we performed high-throughput analyses of small RNAs from various Branchiostoma developmental stages. Our results show that Branchiostoma RdRPs do not appear to participate in RNAi: we did not detect any candidate small RNA population exhibiting classical siRNA length or sequence features. Our results show that RdRPs have been independently lost in dozens of animal clades, and even in a clade where they have been conserved (cephalochordates) their function in RNAi amplification is not preserved. Such a dramatic functional variability reveals an unexpected plasticity in RNA silencing pathways. RNA interference (RNAi) is a conserved gene regulation system in eukaryotes. In non-animal eukaryotes, it necessitates RNA-dependent RNA polymerases (“RdRPs”). Among animals, only nematodes appear to require RdRPs for RNAi. Yet additional animal clades have RdRPs and it is assumed that they participate in RNAi. Here, we find that RdRPs are much more common in animals than previously thought, but their genes were independently lost in many lineages. Focusing on a species with RdRP genes (a cephalochordate), we found that it does not use them for RNAi. While RNAi is the only known function for eukaryotic RdRPs, our results suggest additional roles. Eukaryotic RdRPs thus have a complex evolutionary history in animals, with frequent independent losses and apparent functional diversification.
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Affiliation(s)
- Natalia Pinzón
- Institut de Génétique Humaine, UMR 9002 CNRS and université de Montpellier, 141, rue de la Cardonille, 34396 Montpellier CEDEX 5, France
| | - Stéphanie Bertrand
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins, BIOM, F-66650 Banyuls-sur-Mer, France
| | - Lucie Subirana
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins, BIOM, F-66650 Banyuls-sur-Mer, France
| | - Isabelle Busseau
- Institut de Génétique Humaine, UMR 9002 CNRS and université de Montpellier, 141, rue de la Cardonille, 34396 Montpellier CEDEX 5, France
| | - Hector Escrivá
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins, BIOM, F-66650 Banyuls-sur-Mer, France
| | - Hervé Seitz
- Institut de Génétique Humaine, UMR 9002 CNRS and université de Montpellier, 141, rue de la Cardonille, 34396 Montpellier CEDEX 5, France
- * E-mail:
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17
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Prusa J, Zhu DX, Stallings CL. The stringent response and Mycobacterium tuberculosis pathogenesis. Pathog Dis 2018; 76:5035815. [PMID: 29947752 PMCID: PMC7191866 DOI: 10.1093/femspd/fty054] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 06/08/2018] [Indexed: 12/23/2022] Open
Abstract
During infection, the host restrains Mycobacterium tuberculosis (Mtb) from proliferating by imposing an arsenal of stresses. Despite this onslaught of attacks, Mtb is able to persist for the lifetime of the host, indicating that this pathogen has substantial molecular mechanisms to resist host-inflicted damage. The stringent response is a conserved global stress response in bacteria that involves the production of the hyperphosphorylated guanine nucleotides ppGpp and pppGpp (collectively called (p)ppGpp). (p)ppGpp then regulates a number of cellular processes to adjust the physiology of the bacteria to promote survival in different environments. Survival in the presence of host-generated stresses is an essential quality of successful pathogens, and the stringent response is critical for the intracellular survival of a number of pathogenic bacteria. In addition, the stringent response has been linked to virulence gene expression, persistence, latency and drug tolerance. In Mtb, (p)ppGpp synthesis is required for survival in low nutrient conditions, long term culture and during chronic infection in animal models, all indicative of a strict requirement for (p)ppGpp during exposure to stresses associated with infection. In this review we discuss (p)ppGpp metabolism and how this functions as a critical regulator of Mtb virulence.
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Affiliation(s)
- Jerome Prusa
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Dennis X Zhu
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Christina L Stallings
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
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18
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Wang H, Zhang Y, Yang H, Qin M, Ding X, Liu R, Jiang Y. In Vivo SELEX of an Inhibitory NSCLC-Specific RNA Aptamer from PEGylated RNA Library. MOLECULAR THERAPY-NUCLEIC ACIDS 2017; 10:187-198. [PMID: 29499932 PMCID: PMC5752333 DOI: 10.1016/j.omtn.2017.12.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 01/01/2023]
Abstract
Aptamers are widely used in numerous biochemical, bioanalytical, and biological studies. Most aptamers are developed through an in vitro selection process called SELEX against either purified targets or living cells expressing targets of interest. We report here an in vivo SELEX in mice using a PEGylated RNA library for the identification of a 2'-F RNA aptamer (RA16) that specifically binds to NCI-H460 non-small-cell lung cancer cells with an affinity (KD) of 9 ± 2 nM. Interestingly, RA16 potently inhibited cancer cell proliferation in a dose-dependent manner with an IC50 of 116.7 nM. When tested in vivo in xenografted mice, RA16 showed gradual migration toward tumor and accumulation at tumor site over time. An in vivo anti-cancer study showed that the average inhibition rate for mouse tumors in the RA16-treated group was 54.26% ± 5.87% on day 16 versus the control group. The aptamer RA16 adducted with epirubicin (RA16-epirubicin) showed significantly higher toxicity against targeted NCI-H460 cells and low toxicity against non-targeted tumor cells. Furthermore, RA16-epirubicin adduct exhibited in vivo anti-cancer efficacy, with an inhibition rate of 64.38% ± 7.92% when administrated in H460 xenograft mouse model. In summary, a specific bi-functional RNA aptamer RA16 was selected targeting and inhibiting toward NCI-H460 in vitro and in vivo.
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Affiliation(s)
- Hanlu Wang
- Biopharmaceutical R&D Center, Chinese Academy of Medical Sciences & Peking Union Medical College, Suzhou, Jiangsu 215126, China
| | - Yibang Zhang
- Biopharmagen Corp., Suzhou, Jiangsu 215126, China; Department of Pharmaceutics, School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Haiping Yang
- Biopharmagen Corp., Suzhou, Jiangsu 215126, China
| | - Meng Qin
- Biopharmaceutical R&D Center, Chinese Academy of Medical Sciences & Peking Union Medical College, Suzhou, Jiangsu 215126, China; Biopharmagen Corp., Suzhou, Jiangsu 215126, China
| | - Xinxin Ding
- Biopharmaceutical R&D Center, Chinese Academy of Medical Sciences & Peking Union Medical College, Suzhou, Jiangsu 215126, China; Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721-0207, USA
| | - Rihe Liu
- Biopharmaceutical R&D Center, Chinese Academy of Medical Sciences & Peking Union Medical College, Suzhou, Jiangsu 215126, China; Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy and Carolina Center for Genome Sciences, University of North Carolina, Chapel Hill, NC 27599-7363, USA.
| | - Yongping Jiang
- Biopharmaceutical R&D Center, Chinese Academy of Medical Sciences & Peking Union Medical College, Suzhou, Jiangsu 215126, China; Biopharmagen Corp., Suzhou, Jiangsu 215126, China.
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19
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Kellenberger CA, Hammond MC. In vitro analysis of riboswitch-Spinach aptamer fusions as metabolite-sensing fluorescent biosensors. Methods Enzymol 2014; 550:147-72. [PMID: 25605385 DOI: 10.1016/bs.mie.2014.10.045] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The development of fluorescent biosensors has been motivated by the interest to monitor and measure the levels of specific metabolites in live cells in real time. Common approaches include fusing a protein-based receptor to fluorescent proteins or synthesizing a small molecule reactive probe. Natural metabolite-sensing riboswitches also have been used in reporter-based systems that take advantage of ligand-dependent regulation of downstream gene expression. More recently, it has been shown that RNA-based fluorescent biosensors can be generated by fusing a riboswitch aptamer to the in vitro selected Spinach aptamer, which binds a cell-permeable and conditionally fluorescent molecule. Here, we describe methods to design, prepare, and analyze riboswitch-Spinach aptamer fusion RNAs for ligand-dependent activation of fluorescence in vitro. Examples of procedures to measure fluorescence activation, ligand binding selectivity and affinity, and binding kinetics are given for a cyclic di-GMP-responsive biosensor. The relative ease of in vitro RNA synthesis and purification should make this method accessible to other researchers interested in developing riboswitch-based fluorescent biosensors.
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Affiliation(s)
| | - Ming C Hammond
- Department of Chemistry, University of California, Berkeley, California, USA; Department of Molecular & Cell Biology, University of California, Berkeley, California, USA.
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20
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McCoy LS, Shin D, Tor Y. Isomorphic emissive GTP surrogate facilitates initiation and elongation of in vitro transcription reactions. J Am Chem Soc 2014; 136:15176-84. [PMID: 25255464 PMCID: PMC4227834 DOI: 10.1021/ja5039227] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The fastidious behavior of T7 RNA
polymerase limits the incorporation
of synthetic nucleosides into RNA transcripts, particularly at or
near the promoter. The practically exclusive use of GTP for transcription
initiation further compounds this challenge, and reactions with GTP
analogs, where the heterocyclic nucleus has been altered, have not,
to our knowledge, been demonstrated. The enzymatic incorporation of thGTP, a newly synthesized isomorphic fluorescent nucleotide
with a thieno[3,4-d]pyrimidine core, is explored.
The modified nucleotide can initiate and maintain transcription reactions,
leading to the formation of fully modified and highly emissive RNA
transcripts with thG replacing all guanosine residues.
Short and long modified transcripts are synthesized in comparable
yields to their natural counterparts. To assess proper folding and
function, transcripts were used to assemble a hammerhead ribozyme
with all permutations of natural and modified enzyme and substrate
strands. The thG modified substrate was effectively cleaved
by the natural RNA enzyme, demonstrating the isomorphic features of
the nucleoside and its ability to replace G residues while retaining
proper folding. In contrast, the thG modified enzyme showed
little cleavage ability, suggesting the modifications likely disrupted
the catalytic center, illustrating the significance of the Hoogsteen
face in mediating appropriate contacts. Importantly, the ribozyme
cleavage reaction of the emissive fluorescent transcripts could be
followed in real time by fluorescence spectroscopy. Beyond their utility
as fluorescent probes in biophysical and discovery assays, the results
reported point to the potential utility of such isomorphic nucleosides
in probing specific mechanistic questions in RNA catalysis and RNA
structural analysis.
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Affiliation(s)
- Lisa S McCoy
- Department of Chemistry and Biochemistry, University of California , San Diego, La Jolla, California 92093-0358, United States
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21
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Gagnon JA, Valen E, Thyme SB, Huang P, Ahkmetova L, Pauli A, Montague TG, Zimmerman S, Richter C, Schier AF. Efficient mutagenesis by Cas9 protein-mediated oligonucleotide insertion and large-scale assessment of single-guide RNAs. PLoS One 2014; 9:e98186. [PMID: 24873830 PMCID: PMC4038517 DOI: 10.1371/journal.pone.0098186] [Citation(s) in RCA: 613] [Impact Index Per Article: 61.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 04/18/2014] [Indexed: 11/19/2022] Open
Abstract
The CRISPR/Cas9 system has been implemented in a variety of model organisms to mediate site-directed mutagenesis. A wide range of mutation rates has been reported, but at a limited number of genomic target sites. To uncover the rules that govern effective Cas9-mediated mutagenesis in zebrafish, we targeted over a hundred genomic loci for mutagenesis using a streamlined and cloning-free method. We generated mutations in 85% of target genes with mutation rates varying across several orders of magnitude, and identified sequence composition rules that influence mutagenesis. We increased rates of mutagenesis by implementing several novel approaches. The activities of poor or unsuccessful single-guide RNAs (sgRNAs) initiating with a 5' adenine were improved by rescuing 5' end homogeneity of the sgRNA. In some cases, direct injection of Cas9 protein/sgRNA complex further increased mutagenic activity. We also observed that low diversity of mutant alleles led to repeated failure to obtain frame-shift mutations. This limitation was overcome by knock-in of a stop codon cassette that ensured coding frame truncation. Our improved methods and detailed protocols make Cas9-mediated mutagenesis an attractive approach for labs of all sizes.
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Affiliation(s)
- James A. Gagnon
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Eivind Valen
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Summer B. Thyme
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Peng Huang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Laila Ahkmetova
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Andrea Pauli
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Tessa G. Montague
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Steven Zimmerman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Constance Richter
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Alexander F. Schier
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts, United States of America
- Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, United States of America
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22
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Shrestha P, Xiao S, Dhakal S, Tan Z, Mao H. Nascent RNA transcripts facilitate the formation of G-quadruplexes. Nucleic Acids Res 2014; 42:7236-46. [PMID: 24829453 PMCID: PMC4066803 DOI: 10.1093/nar/gku416] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Recent discovery of the RNA/DNA hybrid G-quadruplexes (HQs) and their potential wide-spread occurrence in human genome during transcription have suggested a new and generic transcriptional control mechanism. The G-rich sequence in which HQ may form can coincide with that for DNA G-quadruplexes (GQs), which are well known to modulate transcriptions. Understanding the molecular interaction between HQ and GQ is, therefore, of pivotal importance to dissect the new mechanism for transcriptional regulation. Using a T7 transcription model, herein we found that GQ and HQ form in a natural sequence, (GGGGA)4, downstream of many transcription start sites. Using a newly-developed single-molecular stalled-transcription assay, we revealed that RNA transcripts helped to populate quadruplexes at the expense of duplexes. Among quadruplexes, HQ predominates GQ in population and mechanical stabilities, suggesting HQ may serve as a better mechanical block during transcription. The fact that HQ and GQ folded within tens of milliseconds in the presence of RNA transcripts provided justification for the co-transcriptional folding of these species. The catalytic role of RNA transcripts in the GQ formation was strongly suggested as the GQ folded >7 times slower without transcription. These results shed light on the possible synergistic effect of GQs and HQs on transcriptional controls.
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Affiliation(s)
- Prakash Shrestha
- Department of Chemistry and Biochemistry and School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Shan Xiao
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P.R. China
| | - Soma Dhakal
- Department of Chemistry and Biochemistry and School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Zheng Tan
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P.R. China
| | - Hanbin Mao
- Department of Chemistry and Biochemistry and School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
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23
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Abstract
Genome editing using the Cas9 endonuclease of Streptococcus pyogenes has demonstrated unprecedented efficacy and facility in a wide variety of biological systems. In zebrafish, specifically, studies have shown that Cas9 can be directed to user-defined genomic target sites via synthetic guide RNAs, enabling random or homology-directed sequence alterations, long-range chromosomal deletions, simultaneous disruption of multiple genes, and targeted integration of several kilobases of DNA. Altogether, these methods are opening new doors for the engineering of knock-outs, conditional alleles, tagged proteins, reporter lines, and disease models. In addition, the ease and high efficiency of generating Cas9-mediated gene knock-outs provides great promise for high-throughput functional genomics studies in zebrafish. In this chapter, we briefly review the origin of CRISPR/Cas technology and discuss current Cas9-based genome-editing applications in zebrafish with particular emphasis on their designs and implementations.
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Affiliation(s)
- Andrew P W Gonzales
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Jing-Ruey Joanna Yeh
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA.
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24
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Vahia AV, Martin CT. Direct tests of the energetic basis of abortive cycling in transcription. Biochemistry 2011; 50:7015-22. [PMID: 21776950 DOI: 10.1021/bi200620q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although the synthesis of RNA from a DNA template is (and must be) a generally very stable process to enable transcription of kilobase transcripts, it has long been known that during initial transcription of the first 8-10 bases of RNA complexes are relatively unstable, leading to the release of short abortive RNA transcripts. A wealth of structural data in the past decade has led to specific mechanistic models elaborating an earlier "stressed intermediate" model for initial transcription. In this study, we test fundamental predictions of each of these models in the simple model enzyme T7 RNA polymerase. Nicking or gapping the nontranscribed template DNA immediately upstream of the growing hybrid yields no systematic reduction in abortive falloff, demonstrating clearly that compaction or "scrunching" of this DNA is not a source of functional instability. Similarly, transcription on DNA in which the nontemplate strand in the initially transcribed region is either mismatched or removed altogether leads to at most modest reductions in abortive falloff, indicating that expansion or "scrunching" of the bubble is not the primary driving force for abortive cycling. Finally, energetic stress derived from the observed steric clash of the growing hybrid against the N-terminal domain contributes at most mildly to abortive cycling, as the addition of steric bulk (additional RNA bases) at the upstream end of the hybrid does not lead to predicted positional shifts in observed abortive patterns. We conclude that while structural changes (scrunching) clearly occur in initial transcription, stress from these changes is not the primary force driving abortive cycling.
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Affiliation(s)
- Ankit V Vahia
- Program in Molecular & Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003, United States
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25
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A system for the continuous directed evolution of biomolecules. Nature 2011; 472:499-503. [PMID: 21478873 PMCID: PMC3084352 DOI: 10.1038/nature09929] [Citation(s) in RCA: 428] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 02/11/2011] [Indexed: 11/11/2022]
Abstract
Laboratory evolution has generated many biomolecules with desired properties, but a single round of mutation, gene expression, screening or selection, and replication typically requires days or longer with frequent human intervention.1 Since evolutionary success is dependent on the total number of rounds performed,2 a means of performing laboratory evolution continuously and rapidly could dramatically enhance its effectiveness.3 While researchers have accelerated individual steps in the evolutionary cycle,4–9 the only previous example of continuous directed evolution was the landmark study of Joyce,10 who continuously evolved RNA ligase ribozymes with an in vitro replication cycle that unfortunately cannot be easily adapted to other biomolecules. Here we describe a system that enables the continuous directed evolution of gene-encoded molecules that can be linked to protein production in E. coli. During phage-assisted continuous evolution (PACE), evolving genes are transferred from host cell to host cell through a modified bacteriophage life cycle in a manner that is dependent on the activity of interest. Dozens of rounds of evolution can occur in a single day of PACE without human intervention. Using PACE, we evolved T7 RNA polymerases that recognize a distinct promoter, initiate transcripts with A instead of G, and initiate transcripts with C. In one example, PACE executed 200 rounds of protein evolution over the course of eight days. Starting from undetectable activity levels in two of these cases, enzymes with each of the three target activities emerged in less than one week of PACE. In all three cases, PACE-evolved polymerase activities exceeded or were comparable to that of the wild-type T7 RNAP on its wild-type promoter, representing improvements of up to several hundred-fold. By greatly accelerating laboratory evolution, PACE may provide solutions to otherwise intractable directed evolution problems and address novel questions about molecular evolution.
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26
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Kore AR, Shanmugasundaram M, Barta TJ. Synthesis and substrate validation of cap analogs containing 7-deazaguanosine moiety by RNA polymerase. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2011; 29:821-30. [PMID: 21128169 DOI: 10.1080/15257770.2010.529860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
An efficient synthesis of new cap analogs containing 7-deazaguanosine moiety such as m(7)G[5']ppp[5'](7-deaza)G and m₂(7,3'O)G[5']ppp[5'](7-deaza)G is described. The biological substrate validation of these new cap analogs is evaluated with respect to its capping efficiency and in vitro T7 RNA polymerase transcription using standard cap m⁷G[5']ppp[5']G as a control. The capping efficiency and HPLC data reveal that these new analogs are not the substrate for T7 RNA polymerase or SP6 RNA polymerase. The present study highlights the importance of the presence of nitrogen atom at N7-position of the guanosine moiety for the polymerase recognition.
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Affiliation(s)
- Anilkumar R Kore
- Life Technologies Corporation, Bioorganic Chemistry Division, 2130 Woodward Street, Austin, TX 78744-1832, USA.
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27
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Staiger N, Marx A. A DNA polymerase with increased reactivity for ribonucleotides and C5-modified deoxyribonucleotides. Chembiochem 2011; 11:1963-6. [PMID: 20734370 DOI: 10.1002/cbic.201000384] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Nadine Staiger
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
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28
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Lodeiro MF, Uchida AU, Arnold JJ, Reynolds SL, Moustafa IM, Cameron CE. Identification of multiple rate-limiting steps during the human mitochondrial transcription cycle in vitro. J Biol Chem 2010; 285:16387-402. [PMID: 20351113 DOI: 10.1074/jbc.m109.092676] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have reconstituted human mitochondrial transcription in vitro on DNA oligonucleotide templates representing the light strand and heavy strand-1 promoters using protein components (RNA polymerase and transcription factors A and B2) isolated from Escherichia coli. We show that 1 eq of each transcription factor and polymerase relative to the promoter is required to assemble a functional initiation complex. The light strand promoter is at least 2-fold more efficient than the heavy strand-1 promoter, but this difference cannot be explained solely by the differences in the interaction of the transcription machinery with the different promoters. In both cases, the rate-limiting step for production of the first phosphodiester bond is open complex formation. Open complex formation requires both transcription factors; however, steps immediately thereafter only require transcription factor B2. The concentration of nucleotide required for production of the first dinucleotide product is substantially higher than that required for subsequent cycles of nucleotide addition. In vitro, promoter-specific differences in post-initiation control of transcription exist, as well as a second rate-limiting step that controls conversion of the transcription initiation complex into a transcription elongation complex. Rate-limiting steps of the biochemical pathways are often those that are targeted for regulation. Like the more complex multisubunit transcription systems, multiple steps may exist for control of transcription in human mitochondria. The tools and mechanistic framework presented here will facilitate not only the discovery of mechanisms regulating human mitochondrial transcription but also interrogation of the structure, function, and mechanism of the complexes that are regulated during human mitochondrial transcription.
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Affiliation(s)
- Maria F Lodeiro
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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29
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Kennedy WP, Momand JR, Yin YW. Mechanism for de novo RNA synthesis and initiating nucleotide specificity by t7 RNA polymerase. J Mol Biol 2007; 370:256-68. [PMID: 17512007 DOI: 10.1016/j.jmb.2007.03.041] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Revised: 03/14/2007] [Accepted: 03/14/2007] [Indexed: 10/23/2022]
Abstract
DNA-directed RNA polymerases are capable of initiating synthesis of RNA without primers, the first catalytic stage of initiation is referred to as de novo RNA synthesis. De novo synthesis is a unique phase in the transcription cycle where the RNA polymerase binds two nucleotides rather than a nascent RNA polymer and a single nucleotide. For bacteriophage T7 RNA polymerase, transcription begins with a marked preference for GTP at the +1 and +2 positions. We determined the crystal structures of T7 RNA polymerase complexes captured during the de novo RNA synthesis. The DNA substrates in the structures in the complexes contain a common Phi 10 duplex promoter followed by a unique five base single-stranded extension of template DNA whose sequences varied at positions +1 and +2, thereby allowing for different pairs of initiating nucleotides GTP, ATP, CTP or UTP to bind. The structures show that the initiating nucleotides bind RNA polymerase in locations distinct from those described previously for elongation complexes. Selection bias in favor of GTP as an initiating nucleotide is accomplished by shape complementarity, extensive protein side-chain and strong base-stacking interactions for the guanine moiety in the enzyme active site. Consequently, an initiating GTP provides the largest stabilization force for the open promoter conformation.
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Affiliation(s)
- William P Kennedy
- Department of Chemistry and Biochemistry, Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
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30
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Ogawa Y, Kato K, Tohya Y, Akashi H. Sequence determination and functional analysis of the Akabane virus (family Bunyaviridae) L RNA segment. Arch Virol 2007; 152:971-9. [PMID: 17216138 DOI: 10.1007/s00705-006-0912-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Accepted: 11/16/2006] [Indexed: 10/23/2022]
Abstract
Akabane virus (AKAV) causes epizootic congenital deformities in cattle, sheep, and goats. Due to the lack of a complete genome sequence, the molecular biological properties of this virus are not known. We have cloned and sequenced the functional large (L) RNA segment of AKAV, and shown that it has polymerase activity using a minireplicon system with RNA polymerase I. The complete L RNA segment is 6868 nucleotides long and encodes an L protein of 2251 amino acids, which functions as an RNA-dependent RNA polymerase. A minireplicon reporter plasmid was constructed by flanking either the firefly luciferase or the green fluorescent protein gene in the antisense orientation with the 5'- and 3'-terminal noncoding regions of the small RNA segment. HmLu-1 cells were transfected with the reporter plasmid, and the L protein and nucleoprotein (N protein) expression plasmids. The reporter activity was upregulated in a dose-dependent manner with increasing concentration of either the L or N protein expression plasmid. Furthermore, the reporter activity could be downregulated by the AKAV NSs protein as well as by other orthobunyaviruses. These results show that the AKAV minireplicon system is a powerful tool for studying transcription and for rescuing infectious viruses from cloned cDNAs.
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Affiliation(s)
- Y Ogawa
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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Amiott EA, Jaehning JA. Mitochondrial transcription is regulated via an ATP "sensing" mechanism that couples RNA abundance to respiration. Mol Cell 2006; 22:329-38. [PMID: 16678105 DOI: 10.1016/j.molcel.2006.03.031] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2005] [Revised: 12/16/2005] [Accepted: 03/30/2006] [Indexed: 11/29/2022]
Abstract
The information encoded in both the nuclear and mitochondrial genomes must be coordinately regulated to respond to changes in cellular growth and energy states. Despite identification of the mitochondrial RNA polymerase (mtRNAP) from several organisms, little is known about mitochondrial transcriptional regulation. Studying the shift from fermentation to respiration in Saccharomyces cerevisiae, we have demonstrated a direct correlation between in vivo changes in mitochondrial transcript abundance and in vitro sensitivity of mitochondrial promoters to ATP concentration (K(m)ATP). Consistent with the idea that the mtRNAP itself senses in vivo ATP levels, we found that transcript abundance correlates with respiration, but only when coupled to mitochondrial ATP synthesis. In addition, we characterized mutations in the mitochondrial promoter and the mtRNAP accessory factor Mtf1 that alter both in vitro K(m)ATP and in vivo transcription in response to respiratory changes. We propose that shifting cellular pools of ATP coordinately control nuclear and mitochondrial transcription.
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Affiliation(s)
- Elizabeth A Amiott
- Department of Biochemistry and Molecular Genetics and Molecular Biology Program, University of Colorado at Denver and Health Sciences Center, MS 8101, P.O. Box 6511, Aurora, 80045, USA
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Blakqori G, Weber F. Efficient cDNA-based rescue of La Crosse bunyaviruses expressing or lacking the nonstructural protein NSs. J Virol 2005; 79:10420-8. [PMID: 16051834 PMCID: PMC1182624 DOI: 10.1128/jvi.79.16.10420-10428.2005] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
La Crosse virus (LACV) belongs to the Bunyaviridae family and causes severe encephalitis in children. It has a negative-sense RNA genome which consists of the three segments L, M, and S. We successfully rescued LACV by transfection of just three plasmids, using a system which was previously established for Bunyamwera virus (Lowen et al., Virology 330:493-500, 2004). These cDNA plasmids represent the three viral RNA segments in the antigenomic orientation, transcribed intracellularly by the T7 RNA polymerase and with the 3' ends trimmed by the hepatitis delta virus ribozyme. As has been shown for Bunyamwera virus, the antigenomic plasmids could serve both as donors for the antigenomic RNA and as support plasmids to provide small amounts of viral proteins for RNA encapsidation and particle formation. In contrast to other rescue systems, however, transfection of additional support plasmids completely abrogated the rescue, indicating that LACV is highly sensitive to overexpression of viral proteins. The BSR-T7/5 cell line, which constitutively expresses T7 RNA polymerase, allowed efficient rescue of LACV, generating approximately 10(8) infectious viruses per milliliter. The utility of this system was demonstrated by the generation of a wild-type virus containing a genetic marker (rLACV) and of a mutant with a deleted NSs gene on the S segment (rLACVdelNSs). The NSs-expressing rLACV formed clear plaques, displayed an efficient host cell shutoff, and was strongly proapoptotic. The rLACVdelNSs mutant, by contrast, exhibited a turbid-plaque phenotype and a less-pronounced shutoff and induced little apoptosis. Nevertheless, both viruses grew in Vero cells to similar titers. Our reverse genetics system now enables us to manipulate the genome of LACV in order to characterize its virulence factors and to develop potential vaccine candidates.
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Affiliation(s)
- Gjon Blakqori
- Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, Universität Freiburg, D-79008 Freiburg, Germany
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Kirby R, Cho EJ, Gehrke B, Bayer T, Park YS, Neikirk DP, McDevitt JT, Ellington AD. Aptamer-based sensor arrays for the detection and quantitation of proteins. Anal Chem 2005; 76:4066-75. [PMID: 15253644 DOI: 10.1021/ac049858n] [Citation(s) in RCA: 221] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aptamer biosensors have been immobilized on beads, introduced into micromachined chips on the electronic tongue sensor array, and used for the detection and quantitation of proteins. Aptamer chips could detect proteins in both capture and sandwich assay formats. Unlike most protein-based arrays, the aptamer chips could be stripped and reused multiple times. The aptamer chips proved to be useful for screening aptamers from in vitro selection experiments and for sensitively quantitating the biothreat agent ricin.
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Affiliation(s)
- Romy Kirby
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA
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Martin CT, Esposito EA, Theis K, Gong P. Structure and function in promoter escape by T7 RNA polymerase. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2005; 80:323-47. [PMID: 16164978 DOI: 10.1016/s0079-6603(05)80008-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
MESH Headings
- Bacteriophage T7/genetics
- Bacteriophage T7/metabolism
- Base Sequence
- DNA, Viral/chemistry
- DNA, Viral/genetics
- DNA, Viral/metabolism
- DNA-Directed RNA Polymerases/chemistry
- DNA-Directed RNA Polymerases/genetics
- DNA-Directed RNA Polymerases/metabolism
- Models, Biological
- Models, Molecular
- Nucleic Acid Conformation
- Peptide Chain Elongation, Translational
- Peptide Chain Initiation, Translational
- Promoter Regions, Genetic
- Protein Conformation
- RNA, Viral/chemistry
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Transcription, Genetic
- Viral Proteins/chemistry
- Viral Proteins/genetics
- Viral Proteins/metabolism
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Affiliation(s)
- Craig T Martin
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
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Ranjith-Kumar CT, Sarisky RT, Gutshall L, Thomson M, Kao CC. De novo initiation pocket mutations have multiple effects on hepatitis C virus RNA-dependent RNA polymerase activities. J Virol 2004; 78:12207-17. [PMID: 15507607 PMCID: PMC525054 DOI: 10.1128/jvi.78.22.12207-12217.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp) has several distinct biochemical activities, including initiation of RNA synthesis by a de novo mechanism, extension from a primed template, nontemplated nucleotide addition, and synthesis of a recombinant RNA product from two or more noncovalently linked templates (template switch). All of these activities require specific interaction with nucleoside triphosphates (NTPs). Based on the structure of the HCV RdRp bound to NTP (S. Bressanelli, L. Tomei, F. A. Rey, and R. DeFrancesco, J. Virol. 76:3482-3492, 2002), we mutated the amino acid residues that contact the putative initiation GTP and examined the effects on the various activities. Although all mutations retained the ability for primer extension, alanine substitution at R48, R158, R386, R394, or D225 decreased de novo initiation, and two or more mutations abolished de novo initiation. While the prototype enzyme had a K(m) for GTP of 3.5 microM, all of the mutations except one had K(m)s that were three- to sevenfold higher. These results demonstrate that the affected residues are functionally required to interact with the initiation nucleotide. Unexpectedly, many of the mutations also affected the addition of nontemplated nucleotide, indicating that residues in the initiating NTP (NTPi)-binding pocket are required for nontemplated nucleotide additions. Interestingly, mutations in D225 are dramatically affected in template switch, indicating that this residue of the NTPi pocket also interacts with components in the elongation complex. We also examined the interaction of ribavirin triphosphate with the NTPi-binding site.
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Affiliation(s)
- C T Ranjith-Kumar
- Department of Biochemistry and Biophysics, Texas A&M University, Mail Stop 2128, College Station, TX 77843, USA
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Matsunaga M, Jaehning JA. A Mutation in the Yeast Mitochondrial Core RNA Polymerase, Rpo41, Confers Defects in Both Specificity Factor Interaction and Promoter Utilization. J Biol Chem 2004; 279:2012-9. [PMID: 14570924 DOI: 10.1074/jbc.m307819200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The yeast mitochondrial RNA polymerase (RNAP) is composed of the core RNAP, Rpo41, and the mitochondrial transcription factor, Mtf1. Both are required for mitochondrial transcription, but how the two proteins interact to create a functional, promoter-selective holoenzyme is still unknown. Rpo41 is similar to the single polypeptide bacteriophage T7RNAP, which does not require additional factors for promoter-selective initiation but whose activity is modulated during infection by association with T7 lysozyme. In this study we used the co-crystal structure of T7RNAP and T7 lysozyme as a model to define a potential Mtf1 interaction surface on Rpo41, making site-directed mutations in Rpo41 at positions predicted to reside at the same location as the T7RNAP/T7 lysozyme interface. We identified Rpo41 mutant E1224A as having reduced interactions with Mtf1 in a two-hybrid assay and a temperature-sensitive petite phenotype in vivo. Although the E1224A mutant has full activity in a non-selective in vitro transcription assay, it is temperature-sensitive for selective transcription from linear DNA templates containing the 14S rRNA, COX2, and tRNAcys mitochondrial promoters. The tRNAcys promoter defect can be rescued by template supercoiling but not by addition of a dinucleotide primer. The fact that mutation of Rpo41 results in selective transcription defects indicates that the core RNAP, like T7RNAP, plays an important role in promoter utilization.
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Affiliation(s)
- Michio Matsunaga
- Department of Biochemistry and Molecular Genetics and Program in Molecular Biology, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, CO 80262, USA
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