1
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Liang Q, Tu B, Cui L. Recombinant T7 RNA polymerase production using ClearColi BL21(DE3) and animal-free media for in vitro transcription. Appl Microbiol Biotechnol 2024; 108:41. [PMID: 38180552 DOI: 10.1007/s00253-023-12939-w] [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: 08/04/2023] [Revised: 10/31/2023] [Accepted: 11/09/2023] [Indexed: 01/06/2024]
Abstract
In vitro transcription (IVT) using T7 RNA polymerase (RNAP) is integral to RNA research, yet producing this enzyme in E. coli presents challenges regarding endotoxins and animal-sourced toxins. This study demonstrates the viable production and characterization of T7 RNAP using ClearColi BL21(DE3) (an endotoxin-free E. coli strain) and animal-free media. Compared to BL21(DE3) with animal-free medium, soluble T7 RNAP expression is ~50% lower in ClearColi BL21(DE3). Optimal soluble T7 RNAP expression in flask fermentation is achieved through the design of experiments (DoE). Specification and functional testing showed that the endotoxin-free T7 RNAP has comparable activity to conventional T7 RNAP. After Ni-NTA purification, endotoxin levels were approximately 109-fold lower than T7 RNAP from BL21(DE3) with animal-free medium. Furthermore, a full factorial DoE created an optimal IVT system that maximized mRNA yield from the endotoxin-free and animal-free T7 RNAP. This work addresses critical challenges in recombinant T7 RNAP production through innovative host and medium combinations, avoided endotoxin risks and animal-derived toxins. Together with an optimized IVT reaction system, this study represents a significant advance for safe and reliable reagent manufacturing and RNA therapeutics. KEY POINTS: • Optimized IVT system maximizes mRNA yields, enabling the synthesis of long RNAs. • Novel production method yields endotoxin-free and animal-free T7 RNAP. • The T7 RNAP has equivalent specifications and function to conventional T7 RNAP.
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Affiliation(s)
- Qianying Liang
- School of Pharmacy & School of Biological and Food Engineering, Changzhou University, Changzhou, 213164, Jiangsu Province, China
| | - Bowen Tu
- Pathogenic Biological Laboratory, Changzhou Disease Control and Prevention Centre, Changzhou Medical Centre, Nanjing Medical University, Changzhou, 213000, Jiangsu Province, China
| | - Lun Cui
- School of Pharmacy & School of Biological and Food Engineering, Changzhou University, Changzhou, 213164, Jiangsu Province, China.
- CCZU-JITRI Joint Bio-X Lab, Changzhou AiRiBio Healthcare CO., LTD, Changzhou, 213164, Jiangsu Province, China.
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2
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Liu Y, Luo Z, Chen X, Yang X, Qi Q, Alifu M, Tao C, Cui W, Liu M, Wang W. Determinants of the interaction between the 5'-leader of HIV-1 genome and human lysyl-tRNA synthetase in reverse transcription primer release process. Biochem Biophys Res Commun 2024; 725:150252. [PMID: 38878758 DOI: 10.1016/j.bbrc.2024.150252] [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: 04/07/2024] [Revised: 06/04/2024] [Accepted: 06/10/2024] [Indexed: 07/06/2024]
Abstract
Reverse transcription of human immunodeficiency virus type 1 (HIV-1) initiates from the 3' end of human tRNALys3. The primer tRNALys3 is selectively packaged into the virus in the form of a complex with human lysyl-tRNA synthetase (LysRS). To facilitate reverse transcription initiation, part of the 5' leader (5'L) of HIV-1 genomic RNA (gRNA) evolves a tRNA anticodon-like element (TLE), which binds LysRS and releases tRNALys3 for primer annealing and reverse transcription initiation. Although TLE has been identified as a key element in 5'L responsible for LysRS binding, how the conformations and various hairpin structures of 5'L regulate 5'L-LysRS interaction is not fully understood. Here, these factors have been individually investigated using direct and competitive fluorescence anisotropy binding experiments. Our data showed that the conformation of 5'L significantly influences its binding affinity with LysRS. The 5'L conformation favoring gRNA dimerization and packaging exhibits much weaker binding affinity with LysRS compared to the alternative 5'L conformation that is not selected for packaging. Additionally, dimerization of 5'L impairs LysRS-5'L interaction. Furthermore, among various regions of 5'L, both the primer binding site/TLE domain and the stem-loop 3 are important for LysRS interaction, whereas the dimerization initiation site and the splicing donor plays a minor role. In contrast, the presence of the transacting responsive and the polyadenylation signal hairpins slightly inhibit LysRS binding. These findings reveal that the conformation and various regions of the 5'L of HIV-1 genome regulate its interaction with human LysRS and the reverse transcription primer release process.
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Affiliation(s)
- Yong Liu
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Zhi Luo
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Xiang Chen
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Xin Yang
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Qi Qi
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Mailikezhati Alifu
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Chengcheng Tao
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Wen Cui
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Mengmeng Liu
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China.
| | - Wei Wang
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China.
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3
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Zhu Y, Chaubey B, Olsen GL, Varani G. Structure of Essential RNA Regulatory Elements in the West Nile Virus 3'-Terminal Stem Loop. J Mol Biol 2024:168767. [PMID: 39214284 DOI: 10.1016/j.jmb.2024.168767] [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: 05/22/2024] [Revised: 08/19/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024]
Abstract
Flaviviruses, such as West Nile and Dengue Virus, pose a significant and growing threat to global health. Central to the flavivirus life cycle are highly structured 5'- and 3'-untranslated regions (UTRs), which harbor conserved cis-acting RNA elements critical for viral replication and host adaptation. Despite their essential roles, detailed molecular insights into these RNA elements have been limited. By employing nuclear magnetic resonance (NMR) spectroscopy in conjunction with SAXS experiments, we determined the three-dimensional structure of the West Nile Virus (WNV) 3'-terminal stem-loop core, a highly conserved element critical for viral genome cyclization and replication. Single nucleotide mutations at several sites within this RNA abolish the ability of the virus to replicate. These critical sites are located within a short 18-nucleotide hairpin stem, a substructure notable for its conformational flexibility, while the adjoining main stem-loop adopts a well-defined extended helix interrupted by three non-Watson-Crick pairs. This study enhances our understanding of several metastable RNA structures that play key roles in regulating the flavivirus lifecycle, and thereby also opens up potential new avenues for the development of antivirals targeting these conserved RNA structures. In particular, the structure we observe suggests that the plastic junction between the small hairpin and the tail of the longer stem-loop could provide a binding pocket for small molecules, for example potentially stabilizing the RNA in a conformation which hinders the conformational rearrangements critical for viral replication.
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Affiliation(s)
- Ying Zhu
- Department of Chemistry, University of Washington, Seattle, WA, USA, 98195
| | - Bhawna Chaubey
- Department of Chemistry, University of Washington, Seattle, WA, USA, 98195
| | - Gregory L Olsen
- Department of Chemistry, University of Washington, Seattle, WA, USA, 98195
| | - Gabriele Varani
- Department of Chemistry, University of Washington, Seattle, WA, USA, 98195.
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4
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Bhola M, Abe K, Orozco P, Rahnamoun H, Avila-Lopez P, Taylor E, Muhammad N, Liu B, Patel P, Marko JF, Starner AC, He C, Van Nostrand EL, Mondragón A, Lauberth SM. RNA interacts with topoisomerase I to adjust DNA topology. Mol Cell 2024:S1097-2765(24)00630-0. [PMID: 39173639 DOI: 10.1016/j.molcel.2024.07.032] [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: 09/28/2022] [Revised: 07/07/2023] [Accepted: 07/31/2024] [Indexed: 08/24/2024]
Abstract
Topoisomerase I (TOP1) is an essential enzyme that relaxes DNA to prevent and dissipate torsional stress during transcription. However, the mechanisms underlying the regulation of TOP1 activity remain elusive. Using enhanced cross-linking and immunoprecipitation (eCLIP) and ultraviolet-cross-linked RNA immunoprecipitation followed by total RNA sequencing (UV-RIP-seq) in human colon cancer cells along with RNA electrophoretic mobility shift assays (EMSAs), biolayer interferometry (BLI), and in vitro RNA-binding assays, we identify TOP1 as an RNA-binding protein (RBP). We show that TOP1 directly binds RNA in vitro and in cells and that most RNAs bound by TOP1 are mRNAs. Using a TOP1 RNA-binding mutant and topoisomerase cleavage complex sequencing (TOP1cc-seq) to map TOP1 catalytic activity, we reveal that RNA opposes TOP1 activity as RNA polymerase II (RNAPII) commences transcription of active genes. We further demonstrate the inhibitory role of RNA in regulating TOP1 activity by employing DNA supercoiling assays and magnetic tweezers. These findings provide insight into the coordinated actions of RNA and TOP1 in regulating DNA topological stress intrinsic to RNAPII-dependent transcription.
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Affiliation(s)
- Mannan Bhola
- Simpson Querrey Institute for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Kouki Abe
- Simpson Querrey Institute for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Paola Orozco
- Section of Molecular Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Homa Rahnamoun
- Section of Molecular Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Pedro Avila-Lopez
- Simpson Querrey Institute for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Elijah Taylor
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208-3108, USA
| | - Nefertiti Muhammad
- Simpson Querrey Institute for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Bei Liu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
| | - Prachi Patel
- Simpson Querrey Institute for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - John F Marko
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208-3108, USA
| | - Anne C Starner
- Verna & Marrs McLean Department of Biochemistry & Molecular Pharmacology and Therapeutic Innovation Center, Baylor College of Medicine, Houston, TX, USA
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Eric L Van Nostrand
- Verna & Marrs McLean Department of Biochemistry & Molecular Pharmacology and Therapeutic Innovation Center, Baylor College of Medicine, Houston, TX, USA
| | - Alfonso Mondragón
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208-3108, USA
| | - Shannon M Lauberth
- Simpson Querrey Institute for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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5
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Steinbuch KB, Cong D, Rodriguez AJ, Tor Y. Emissive Guanosine Analog Applicable for Real-Time Live Cell Imaging. ACS Chem Biol 2024; 19:1836-1841. [PMID: 39101365 PMCID: PMC11334113 DOI: 10.1021/acschembio.4c00398] [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: 06/07/2024] [Revised: 07/16/2024] [Accepted: 07/26/2024] [Indexed: 08/06/2024]
Abstract
A new emissive guanosine analog CF3thG, constructed by a single trifluoromethylation step from the previously reported thG, displays red-shifted absorption and emission spectra compared to its precursor. The impact of solvent type and polarity on the photophysical properties of CF3thG suggests that the electronic effects of the trifluoromethyl group dominate its behavior and demonstrates its susceptibility to microenvironmental polarity changes. In vitro transcription initiations using T7 RNA polymerase, initiated with CF3thG, result in highly emissive 5'-labeled RNA transcripts, demonstrating the tolerance of the enzyme toward the analog. Viability assays with HEK293T cells displayed no detrimental effects at tested concentrations, indicating the safety of the analog for cellular applications. Live cell imaging of the free emissive guanosine analog using confocal microscopy was facilitated by its red-shifted absorption and emission and adequate brightness. Real-time live cell imaging demonstrated the release of the guanosine analog from HEK293T cells at concentration-gradient conditions, which was suppressed by the addition of guanosine.
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Affiliation(s)
- Kfir B. Steinbuch
- Department of Chemistry and
Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093-0358, United
States
| | - Deyuan Cong
- Department of Chemistry and
Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093-0358, United
States
| | - Anthony J. Rodriguez
- Department of Chemistry and
Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093-0358, United
States
| | - Yitzhak Tor
- Department of Chemistry and
Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093-0358, United
States
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6
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Li S, Chu Y, Guo X, Mao C, Xiao SJ. Circular RNA oligonucleotides: enzymatic synthesis and scaffolding for nanoconstruction. NANOSCALE HORIZONS 2024. [PMID: 39042106 DOI: 10.1039/d4nh00236a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
We report the efficient synthesis of monomeric circular RNAs (circRNAs) in the size range of 16-44 nt with a novel DNA dumbbell splinting plus T4 DNA ligation strategy. Such a DNA dumbbell splinting strategy was developed by one group among ours recently for near-quantitative conversion of short linear DNAs into monomeric circular ones. Furthermore, using the 44 nt circRNA as scaffold strands, we constructed hybrid RNA:DNA and pure RNA:RNA double crossover tiles and their assemblies of nucleic acid nanotubes and flat arrays.
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Affiliation(s)
- Shijie Li
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Yanxin Chu
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Xin Guo
- Bruker (Beijing) Scientific Technology Co. Ltd, China
| | - Chengde Mao
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.
| | - Shou-Jun Xiao
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
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7
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Schaffter SW, Kengmana E, Fern J, Byrne SR, Schulman R. Strategies to Reduce Promoter-Independent Transcription of DNA Nanostructures and Strand Displacement Complexes. ACS Synth Biol 2024; 13:1964-1977. [PMID: 38885464 DOI: 10.1021/acssynbio.3c00726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Bacteriophage RNA polymerases, in particular T7 RNA polymerase (RNAP), are well-characterized and popular enzymes for many RNA applications in biotechnology both in vitro and in cellular settings. These monomeric polymerases are relatively inexpensive and have high transcription rates and processivity to quickly produce large quantities of RNA. T7 RNAP also has high promoter-specificity on double-stranded DNA (dsDNA) such that it only initiates transcription downstream of its 17-base promoter site on dsDNA templates. However, there are many promoter-independent T7 RNAP transcription reactions involving transcription initiation in regions of single-stranded DNA (ssDNA) that have been reported and characterized. These promoter-independent transcription reactions are important to consider when using T7 RNAP transcriptional systems for DNA nanotechnology and DNA computing applications, in which ssDNA domains often stabilize, organize, and functionalize DNA nanostructures and facilitate strand displacement reactions. Here we review the existing literature on promoter-independent transcription by bacteriophage RNA polymerases with a specific focus on T7 RNAP, and provide examples of how promoter-independent reactions can disrupt the functionality of DNA strand displacement circuit components and alter the stability and functionality of DNA-based materials. We then highlight design strategies for DNA nanotechnology applications that can mitigate the effects of promoter-independent T7 RNAP transcription. The design strategies we present should have an immediate impact by increasing the rate of success of using T7 RNAP for applications in DNA nanotechnology and DNA computing.
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Affiliation(s)
- Samuel W Schaffter
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Eli Kengmana
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Joshua Fern
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Shane R Byrne
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Rebecca Schulman
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
- Department of Computer Science, Johns Hopkins University, Baltimore, Maryland 21218, United States
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8
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Syu YC, Hatterschide J, Budding CR, Tang Y, Musier-Forsyth K. Human T-cell leukemia virus type 1 uses a specific tRNA Pro isodecoder to prime reverse transcription. RNA (NEW YORK, N.Y.) 2024; 30:967-976. [PMID: 38684316 PMCID: PMC11251516 DOI: 10.1261/rna.080006.124] [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: 02/24/2024] [Accepted: 04/08/2024] [Indexed: 05/02/2024]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the only oncogenic human retrovirus discovered to date. All retroviruses are believed to use a host cell tRNA to prime reverse transcription (RT). In HTLV-1, the primer-binding site (PBS) in the genomic RNA is complementary to the 3' 18 nucleotides (nt) of human tRNAPro The human genome encodes 20 cytoplasmic tRNAPro genes representing seven isodecoders, all of which share the same 3' 18 nt sequence but vary elsewhere. Whether all tRNAPro isodecoders are used to prime RT in cells is unknown. A previous study showed that a 3' 18 nt tRNAPro-derived fragment (tRFPro) is packaged into HTLV-1 particles and can serve as an RT primer in vitro. The role of this tRNA fragment in the viral life cycle is unclear. In retroviruses, N1-methylation of the tRNA primer at position A58 (m1A) is essential for successful plus-strand transfer. Using primer-extension assays performed in chronically HTLV-1-infected cells, we found that A58 of tRNAPro is m1A-modified, implying that full-length tRNAPro is capable of facilitating successful plus-strand transfer. Analysis of HTLV-1 RT primer extension products indicated that full-length tRNAPro is likely to be the primer. To determine which tRNAPro isodecoder is used as the RT primer, we sequenced the minus-strand strong-stop RT product containing the intact tRNA primer and established that HTLV-1 primes RT using a specific tRNAPro UGG isodecoder. Further studies are required to understand how this primer is annealed to the highly structured HTLV-1 PBS and to investigate the role of tRFPro in the viral life cycle.
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Affiliation(s)
- Yu-Ci Syu
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, Ohio 43210, USA
| | - Joshua Hatterschide
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, Ohio 43210, USA
| | - Christina R Budding
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, Ohio 43210, USA
| | - Yingke Tang
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, Ohio 43210, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, Ohio 43210, USA
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9
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MalagodaPathiranage K, Banerjee R, Martin CT. A new approach to RNA synthesis: immobilization of stably and functionally co-tethered promoter DNA and T7 RNA polymerase. Nucleic Acids Res 2024:gkae599. [PMID: 39011885 DOI: 10.1093/nar/gkae599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 06/11/2024] [Accepted: 06/30/2024] [Indexed: 07/17/2024] Open
Abstract
Current approaches to RNA synthesis/manufacturing require substantial (and incomplete) purification post-synthesis. We have previously demonstrated the synthesis of RNA from a complex in which T7 RNA polymerase is tethered to promoter DNA. In the current work, we extend this approach to demonstrate an extremely stable system of functional co-tethered complex to a solid support. Using the system attached to magnetic beads, we carry out more than 20 rounds of synthesis using the initial polymerase-DNA construct. We further demonstrate the wide utility of this system in the synthesis of short RNA, a CRISPR guide RNA, and a protein-coding mRNA. In all cases, the generation of self-templated double stranded RNA (dsRNA) impurities are greatly reduced, by both the tethering itself and by the salt-tolerance that local co-tethering provides. Transfection of the mRNA into HEK293T cells shows a correlation between added salt in the transcription reaction (which inhibits RNA rebinding that generates RNA-templated extensions) and significantly increased expression and reduced innate immune stimulation by the mRNA reaction product. These results point in the direction of streamlined processes for synthesis/manufacturing of high-quality RNA of any length, and at greatly reduced costs.
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Affiliation(s)
| | - Ruptanu Banerjee
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Craig T Martin
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003, USA
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10
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Lenk R, Kleindienst W, Szabó GT, Baiersdörfer M, Boros G, Keller JM, Mahiny AJ, Vlatkovic I. Understanding the impact of in vitro transcription byproducts and contaminants. Front Mol Biosci 2024; 11:1426129. [PMID: 39050733 PMCID: PMC11266732 DOI: 10.3389/fmolb.2024.1426129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 06/14/2024] [Indexed: 07/27/2024] Open
Abstract
The success of messenger (m)RNA-based vaccines against SARS-CoV-2 during the COVID-19 pandemic has led to rapid growth and innovation in the field of mRNA-based therapeutics. However, mRNA production, whether in small amounts for research or large-scale GMP-grade for biopharmaceutics, is still based on the In Vitro Transcription (IVT) reaction developed in the early 1980s. The IVT reaction exploits phage RNA polymerase to catalyze the formation of an engineered mRNA that depends on a linearized DNA template, nucleotide building blocks, as well as pH, temperature, and reaction time. But depending on the IVT conditions and subsequent purification steps, diverse byproducts such as dsRNA, abortive RNAs and RNA:DNA hybrids might form. Unwanted byproducts, if not removed, could be formulated together with the full-length mRNA and cause an immune response in cells by activating host pattern recognition receptors. In this review, we summarize the potential types of IVT byproducts, their known biological activity, and how they can impact the efficacy and safety of mRNA therapeutics. In addition, we briefly overview non-nucleotide-based contaminants such as RNases, endotoxin and metal ions that, when present in the IVT reaction, can also influence the activity of mRNA-based drugs. We further discuss current approaches aimed at adjusting the IVT reaction conditions or improving mRNA purification to achieve optimal performance for medical applications.
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11
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Hien EDM, Chauvier A, St-Pierre P, Lafontaine DA. Structural Characterization of the Cotranscriptional Folding of the Thiamin Pyrophosphate Sensing thiC Riboswitch in Escherichia coli. Biochemistry 2024; 63:1608-1620. [PMID: 38864595 DOI: 10.1021/acs.biochem.3c00665] [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: 06/13/2024]
Abstract
Riboswitches are RNA-regulating elements that mostly rely on structural changes to modulate gene expression at various levels. Recent studies have revealed that riboswitches may control several regulatory mechanisms cotranscriptionally, i.e., during the transcription elongation of the riboswitch or early in the coding region of the regulated gene. Here, we study the structure of the nascent thiamin pyrophosphate (TPP)-sensing thiC riboswitch in Escherichia coli by using biochemical and enzymatic conventional probing approaches. Our chemical (in-line and lead probing) and enzymatic (nucleases S1, A, T1, and RNase H) probing data provide a comprehensive model of how TPP binding modulates the structure of the thiC riboswitch. Furthermore, by using transcriptional roadblocks along the riboswitch sequence, we find that a certain portion of nascent RNA is needed to sense TPP that coincides with the formation of the P5 stem loop. Together, our data suggest that conventional techniques may readily be used to study cotranscriptional folding of nascent RNAs.
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Affiliation(s)
- Elsa D M Hien
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Adrien Chauvier
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Patrick St-Pierre
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Daniel A Lafontaine
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
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12
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Tian Z, Shao D, Tang L, Li Z, Chen Q, Song Y, Li T, Simmel FC, Song J. Circular single-stranded DNA as a programmable vector for gene regulation in cell-free protein expression systems. Nat Commun 2024; 15:4635. [PMID: 38821953 PMCID: PMC11143192 DOI: 10.1038/s41467-024-49021-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 05/22/2024] [Indexed: 06/02/2024] Open
Abstract
Cell-free protein expression (CFE) systems have emerged as a critical platform for synthetic biology research. The vectors for protein expression in CFE systems mainly rely on double-stranded DNA and single-stranded RNA for transcription and translation processing. Here, we introduce a programmable vector - circular single-stranded DNA (CssDNA), which is shown to be processed by DNA and RNA polymerases for gene expression in a yeast-based CFE system. CssDNA is already widely employed in DNA nanotechnology due to its addressability and programmability. To apply above methods in the context of synthetic biology, CssDNA can not only be engineered for gene regulation via the different pathways of sense CssDNA and antisense CssDNA, but also be constructed into several gene regulatory logic gates in CFE systems. Our findings advance the understanding of how CssDNA can be utilized in gene expression and gene regulation, and thus enrich the synthetic biology toolbox.
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Affiliation(s)
- Zhijin Tian
- Department of Chemistry, University of Science & Technology of China, Hefei, Anhui, 230026, China
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, Zhejiang, 310022, China
| | - Dandan Shao
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Linlin Tang
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, Zhejiang, 310022, China
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhen Li
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Qian Chen
- College of Forestry, Northeast Forestry University, Harbin, 150040, Heilongjiang, China
| | - Yongxiu Song
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, Zhejiang, 310022, China
- Ningbo institute of Dalian University of Technology, Ningbo, 315016, China
| | - Tao Li
- Department of Chemistry, University of Science & Technology of China, Hefei, Anhui, 230026, China
| | - Friedrich C Simmel
- Department of Bioscience, School of Natural Sciences, Technische Universität München, Garching, Germany
| | - Jie Song
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, Zhejiang, 310022, China.
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
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13
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Clark NE, Schraut MR, Winters RA, Kearns K, Scanlon TC. An immuno-northern technique to measure the size of dsRNA byproducts in in vitro transcribed RNA. Electrophoresis 2024. [PMID: 38785136 DOI: 10.1002/elps.202400036] [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: 02/22/2024] [Revised: 05/01/2024] [Accepted: 05/04/2024] [Indexed: 05/25/2024]
Abstract
Double-stranded RNA is an immunogenic byproduct present in RNA synthesized with in vitro transcription. dsRNA byproducts engage virus-sensing innate immunity receptors and cause inflammation. Removing dsRNA from in vitro transcribed messenger RNA (mRNA) reduces immunogenicity and improves protein translation. Levels of dsRNA are typically 0.1%-0.5% of total transcribed RNA. Because they form such a minor fraction of the total RNA in transcription reactions, it is difficult to confidently identify discrete bands on agarose gels that correspond to the dsRNA byproducts. Thus, the sizes of dsRNA byproducts are largely unknown. Total levels of dsRNA are typically assayed with dsRNA-specific antibodies in ELISA and immuno dot-blot assays. Here we report a dsRNA-specific immuno-northern blot technique that provides a clear picture of the dsRNA size distributions in transcribed RNA. This technique could complement existing dsRNA analytical methods in studies of dsRNA byproduct synthesis, dsRNA removal, and characterization of therapeutic RNA drug substances.
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14
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Tipo J, Gottipati K, Slaton M, Gonzalez-Gutierrez G, Choi KH. Structure of HIV-1 RRE stem-loop II identifies two conformational states of the high-affinity Rev binding site. Nat Commun 2024; 15:4198. [PMID: 38760344 PMCID: PMC11101469 DOI: 10.1038/s41467-024-48162-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 04/22/2024] [Indexed: 05/19/2024] Open
Abstract
During HIV infection, specific RNA-protein interaction between the Rev response element (RRE) and viral Rev protein is required for nuclear export of intron-containing viral mRNA transcripts. Rev initially binds the high-affinity site in stem-loop II, which promotes oligomerization of additional Rev proteins on RRE. Here, we present the crystal structure of RRE stem-loop II in distinct closed and open conformations. The high-affinity Rev-binding site is located within the three-way junction rather than the predicted stem IIB. The closed and open conformers differ in their non-canonical interactions within the three-way junction, and only the open conformation has the widened major groove conducive to initial Rev interaction. Rev binding assays show that RRE stem-loop II has high- and low-affinity binding sites, each of which binds a Rev dimer. We propose a binding model, wherein Rev-binding sites on RRE are sequentially created through structural rearrangements induced by Rev-RRE interactions.
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Affiliation(s)
- Jerricho Tipo
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
| | - Keerthi Gottipati
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
| | - Michael Slaton
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
| | | | - Kyung H Choi
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, TX, 77555, USA.
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA.
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology, The University of Texas Medical Branch, Galveston, TX, 77555, USA.
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15
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Matsuda T, Hori H, Yamagami R. Rational design of oligonucleotides for enhanced in vitro transcription of small RNA. RNA (NEW YORK, N.Y.) 2024; 30:710-727. [PMID: 38423625 PMCID: PMC11098460 DOI: 10.1261/rna.079923.123] [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: 12/10/2023] [Accepted: 02/14/2024] [Indexed: 03/02/2024]
Abstract
All kinds of RNA molecules can be produced by in vitro transcription using T7 RNA polymerase using DNA templates obtained by solid-phase chemical synthesis, primer extension, PCR, or DNA cloning. The oligonucleotide design, however, is a challenge to nonexperts as this relies on a set of rules that have been established empirically over time. Here, we describe a Python program to facilitate the rational design of oligonucleotides, calculated with kinetic parameters for enhanced in vitro transcription (ROCKET). The Python tool uses thermodynamic parameters, performs folding-energy calculations, and selects oligonucleotides suitable for the polymerase extension reaction. These oligonucleotides improve yields of template DNA. With the oligonucleotides selected by the program, the tRNA transcripts can be prepared by a one-pot reaction of the DNA polymerase extension reaction and the transcription reaction. Also, the ROCKET-selected oligonucleotides provide greater transcription yields than that from oligonucleotides selected by Primerize, a leading software for designing oligonucleotides for in vitro transcription, due to the enhancement of template DNA synthesis. Apart from over 50 tRNA genes tested, an in vitro transcribed self-cleaving ribozyme was found to have catalytic activity. In addition, the program can be applied to the synthesis of mRNA, demonstrating the wide applicability of the ROCKET software.
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MESH Headings
- Transcription, Genetic
- Oligonucleotides/chemistry
- Oligonucleotides/genetics
- Oligonucleotides/chemical synthesis
- Software
- DNA-Directed RNA Polymerases/metabolism
- DNA-Directed RNA Polymerases/genetics
- RNA, Catalytic/genetics
- RNA, Catalytic/metabolism
- RNA, Catalytic/chemistry
- Thermodynamics
- RNA, Transfer/genetics
- RNA, Transfer/chemistry
- RNA, Transfer/metabolism
- Kinetics
- RNA, Messenger/genetics
- RNA, Messenger/chemistry
- RNA, Messenger/metabolism
- Viral Proteins/genetics
- Viral Proteins/metabolism
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Affiliation(s)
- Teppei Matsuda
- Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Hiroyuki Hori
- Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Ryota Yamagami
- Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, Matsuyama, Ehime 790-8577, Japan
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16
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Sari Y, Sousa Rosa S, Jeffries J, Marques MPC. Comprehensive evaluation of T7 promoter for enhanced yield and quality in mRNA production. Sci Rep 2024; 14:9655. [PMID: 38671016 PMCID: PMC11053036 DOI: 10.1038/s41598-024-59978-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 04/17/2024] [Indexed: 04/28/2024] Open
Abstract
The manufacturing of mRNA vaccines relies on cell-free based systems that are easily scalable and flexible compared with the traditional vaccine manufacturing processes. Typically, standard processes yield 2 to 5 g L-1 of mRNA, with recent process optimisations increasing yields to 12 g L-1. However, increasing yields can lead to an increase in the production of unwanted by-products, namely dsRNA. It is therefore imperative to reduce dsRNA to residual levels in order to avoid intensive purification steps, enabling cost-effective manufacturing processes. In this work, we exploit sequence modifications downstream of the T7 RNA polymerase promoter to increase mRNA yields whilst simultaneously minimising dsRNA. In particular, transcription performance was optimised by modifying the sequence downstream of the T7 promoter with additional AT-rich sequences. We have identified variants that were able to produce higher amounts of mRNA (up to 14 g L-1) in 45 min of reaction. These variants exhibited up to a 30% reduction in dsRNA byproduct levels compared to a wildtype T7 promoter, and have similar EGFP protein expression. The results show that optimising the non-coding regions can have an impact on mRNA production yields and quality, reducing overall manufacturing costs.
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Affiliation(s)
- Yustika Sari
- Department of Biochemical Engineering, University College London, Gordon Street, London, WC1E 6BT, UK
| | - Sara Sousa Rosa
- Department of Biochemical Engineering, University College London, Gordon Street, London, WC1E 6BT, UK
- Department of Bioengineering, iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB-Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Jack Jeffries
- Department of Biochemical Engineering, University College London, Gordon Street, London, WC1E 6BT, UK
| | - Marco P C Marques
- Department of Biochemical Engineering, University College London, Gordon Street, London, WC1E 6BT, UK.
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17
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Pichon M, Levi-Acobas F, Kitoun C, Hollenstein M. 2',3'-Protected Nucleotides as Building Blocks for Enzymatic de novo RNA Synthesis. Chemistry 2024; 30:e202400137. [PMID: 38403849 DOI: 10.1002/chem.202400137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/13/2024] [Accepted: 02/20/2024] [Indexed: 02/27/2024]
Abstract
Besides being a key player in numerous fundamental biological processes, RNA also represents a versatile platform for the creation of therapeutic agents and efficient vaccines. The production of RNA oligonucleotides, especially those decorated with chemical modifications, cannot meet the exponential demand. Due to the inherent limits of solid-phase synthesis and in vitro transcription, alternative, biocatalytic approaches are in dire need to facilitate the production of RNA oligonucleotides. Here, we present a first step towards the controlled enzymatic synthesis of RNA oligonucleotides. We have explored the possibility of a simple protection step of the vicinal cis-diol moiety to temporarily block ribonucleotides. We demonstrate that pyrimidine nucleotides protected with acetals, particularly 2',3'-O-isopropylidene, are well-tolerated by the template-independent RNA polymerase PUP (polyU polymerase) and highly efficient coupling reactions can be achieved within minutes - an important feature for the development of enzymatic de novo synthesis protocols. Even though purines are not equally well-tolerated, these findings clearly demonstrate the possibility of using cis-diol-protected ribonucleotides combined with template-independent polymerases for the stepwise construction of RNA oligonucleotides.
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Affiliation(s)
- Maëva Pichon
- Institut Pasteur, Université Paris Cité, CNRS UMR3523, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, 28, rue du Docteur Roux, 75724, Paris Cedex 15, France
| | - Fabienne Levi-Acobas
- Institut Pasteur, Université Paris Cité, CNRS UMR3523, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, 28, rue du Docteur Roux, 75724, Paris Cedex 15, France
| | - Camélia Kitoun
- Institut Pasteur, Université Paris Cité, CNRS UMR3523, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, 28, rue du Docteur Roux, 75724, Paris Cedex 15, France
| | - Marcel Hollenstein
- Institut Pasteur, Université Paris Cité, CNRS UMR3523, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, 28, rue du Docteur Roux, 75724, Paris Cedex 15, France
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18
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Sawant AA, Tripathi S, Galande S, Rajamani S. A Prebiotic Genetic Nucleotide as an Early Darwinian Ancestor for Pre-RNA Evolution. ACS OMEGA 2024; 9:18072-18082. [PMID: 38680342 PMCID: PMC11044211 DOI: 10.1021/acsomega.3c09949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/22/2024] [Accepted: 03/29/2024] [Indexed: 05/01/2024]
Abstract
Prebiotic genetic nucleotides (PGNs) often outcompete canonical alphabets in the formation of nucleotides and subsequent RNA oligomerization under early Earth conditions. This indicates that the early genetic code might have been dominated by pre-RNA that contained PGNs for information transfer and catalysis. Despite this, deciphering pre-RNAs' capacity to acquire function and delineating their evolutionary transition to a canonical RNA World has remained under-researched in the origins of life (OoL) field. We report the synthesis of a prebiotically relevant nucleotide (BaTP) containing the noncanonical nucleobase barbituric acid. We demonstrate the first instance of its enzymatic incorporation into an RNA, using a T7 RNA polymerase. BaTP's incorporation into baby spinach aptamer allowed it to retain its overall secondary structure and function. Finally, we also demonstrate faithful transfer of information from the pre-RNA-containing BaTP to DNA, using a high-fidelity RNA-dependent DNA polymerase, alluding to how selection pressures and complexities could have ensued during the molecular evolution of the early genetic code.
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Affiliation(s)
- Anupam A. Sawant
- Department
of Biology, Indian Institute of Science
Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune, Maharashtra 411008, India
| | - Sneha Tripathi
- Department
of Biology, Indian Institute of Science
Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune, Maharashtra 411008, India
| | - Sanjeev Galande
- Department
of Biology, Indian Institute of Science
Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune, Maharashtra 411008, India
- Center
of Excellence in Epigenetics, Department of Life Sciences, School
of Natural Sciences, Shiv Nadar Institution
of Eminence, Gautam Buddha
Nagar, Uttar Pradesh 201314, India
| | - Sudha Rajamani
- Department
of Biology, Indian Institute of Science
Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune, Maharashtra 411008, India
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19
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De Vos J, Morreel K, Alvarez P, Vanluchene H, Vankeirsbilck R, Sandra P, Sandra K. Evaluation of size-exclusion chromatography, multi-angle light scattering detection and mass photometry for the characterization of mRNA. J Chromatogr A 2024; 1719:464756. [PMID: 38402695 DOI: 10.1016/j.chroma.2024.464756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 02/27/2024]
Abstract
The recent approval of messenger ribonucleic acid (mRNA) as vaccine to combat the COVID-19 pandemic has been a scientific turning point. Today, the applicability of mRNA is being demonstrated beyond infectious diseases, for example in cancer immunotherapy, protein replacement therapy and gene editing. mRNA is produced by in vitro transcription (IVT) from a linear DNA template and modified at the 3' and 5' ends to improve translational efficiency and stability. Co-existing impurities such as RNA fragments and double-stranded RNA (dsRNA), amongst others, can drastically impact mRNA quality and efficacy. In this study, size-exclusion chromatography (SEC) is evaluated for the characterization of IVT-mRNA. The effect of mobile phase composition (ionic strength and organic modifier), pH, column temperature and pore size (300 Å, 1000 Å, and 2000 Å) on the separation performance and structural integrity of IVT-mRNA varying in size is described. Non-replicating, self-amplifying (saRNA), temperature degraded, and ribonuclease (RNase) digested mRNA, the latter to characterize the 3' poly(A) tail, were included in the study. Beyond ultraviolet (UV) detection, refractive index (RI) and multi-angle light scattering (MALS) detection were implemented to accurately determine molecular weight (MW) of mRNA. Finally, mass photometry is introduced as a complementary methodology to study mRNA under native conditions.
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Affiliation(s)
- Jelle De Vos
- RIC group, President Kennedypark 6, 8500 Kortrijk, Belgium
| | - Kris Morreel
- RIC group, President Kennedypark 6, 8500 Kortrijk, Belgium
| | - Piotr Alvarez
- RIC group, President Kennedypark 6, 8500 Kortrijk, Belgium
| | | | | | - Pat Sandra
- RIC group, President Kennedypark 6, 8500 Kortrijk, Belgium
| | - Koen Sandra
- RIC group, President Kennedypark 6, 8500 Kortrijk, Belgium.
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20
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McKenney KM, Connacher RP, Dunshee EB, Goldstrohm AC. Chemi-Northern: a versatile chemiluminescent northern blot method for analysis and quantitation of RNA molecules. RNA (NEW YORK, N.Y.) 2024; 30:448-462. [PMID: 38282416 PMCID: PMC10946428 DOI: 10.1261/rna.079880.123] [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: 10/24/2023] [Accepted: 01/10/2024] [Indexed: 01/30/2024]
Abstract
This report describes a chemiluminescence-based detection method for RNAs on northern blots, designated Chemi-Northern. This approach builds on the simplicity and versatility of northern blotting, while dispensing of the need for expensive and cumbersome radioactivity. RNAs are first separated by denaturing gel electrophoresis, transferred to a nylon membrane, and then hybridized to a biotinylated RNA or DNA antisense probe. Streptavidin conjugated with horseradish peroxidase and enhanced chemiluminescence substrate are then used to detect the probe bound to the target RNA. Our results demonstrate the versatility of this method in detecting natural and engineered RNAs expressed in cells, including messenger and noncoding RNAs. We show that Chemi-Northern detection is sensitive and fast, detecting attomole amounts of RNA in as little as 1 sec, with high signal intensity and low background. The dynamic response displays excellent linearity. Using Chemi-Northern, we measure the reproducible, statistically significant reduction of mRNA levels by human sequence-specific RNA-binding proteins, PUM1 and PUM2. Additionally, we measure the interaction of the poly(A) binding protein, PABPC1, with polyadenylated mRNA. Thus, the Chemi-Northern method provides a versatile, simple, and cost-effective method to enable researchers to analyze expression, processing, binding, and decay of RNAs.
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Affiliation(s)
- Katherine M McKenney
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Robert P Connacher
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Elise B Dunshee
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Aaron C Goldstrohm
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
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21
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Anders AG, Tidwell ED, Gadkari VV, Koutmos M, Ruotolo BT. Collision-Induced Unfolding Reveals Disease-Associated Stability Shifts in Mitochondrial Transfer Ribonucleic Acids. J Am Chem Soc 2024; 146:4412-4420. [PMID: 38329282 DOI: 10.1021/jacs.3c09230] [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] [Indexed: 02/09/2024]
Abstract
Ribonucleic acids (RNAs) remain challenging targets for structural biology, creating barriers to understanding their vast functions in cellular biology and fully realizing their applications in biotechnology. The inherent dynamism of RNAs creates numerous obstacles in capturing their biologically relevant higher-order structures (HOSs), and as a result, many RNA functions remain unknown. In this study, we describe the development of native ion mobility-mass spectrometry and collision-induced unfolding (CIU) for the structural characterization of a variety of RNAs. We evaluate the ability of these techniques to preserve native structural features in the gas phase across a wide range of functional RNAs. Finally, we apply these tools to study the elusive mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes-associated A3243G mutation. Our data demonstrate that our experimentally determined conditions preserve some solution-state memory of RNAs via the correlated complexity of CIU fingerprints and RNA HOS, the observation of predicted stability shifts in the control RNA samples, and the retention of predicted magnesium binding events in gas-phase RNA ions. Significant differences in collision cross section and stability are observed as a function of the A3243G mutation across a subset of the mitochondrial tRNA maturation pathway. We conclude by discussing the potential application of CIU for the development of RNA-based biotherapeutics and, more broadly, transcriptomic characterization.
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Affiliation(s)
- Anna G Anders
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Elizabeth D Tidwell
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Varun V Gadkari
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Markos Koutmos
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brandon T Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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22
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Hengelbrock A, Schmidt A, Strube J. Digital Twin Fundamentals of mRNA In Vitro Transcription in Variable Scale Toward Autonomous Operation. ACS OMEGA 2024; 9:8204-8220. [PMID: 38405539 PMCID: PMC10882708 DOI: 10.1021/acsomega.3c08732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/27/2024]
Abstract
The COVID-19 pandemic caused the rapid development of mRNA (messenger ribonucleic acid) vaccines and new RNA-based therapeutic methods. However, the approval rate for candidates has the potential to be increased, with a significant number failing so far due to efficacy, safety, and manufacturing deficiencies, hindering equitable vaccine distribution during pandemics. This study focuses on optimizing the production of mRNA, a critical component of mRNA-based vaccines, using a scalable machine by investigating the key mechanisms of mRNA in vitro transcription. First, kinetic parameters for the mRNA production process were determined. The validity of the determination and the robustness of the model are demonstrated by predicting different reactions with and without substrate limitations as well as different transcripts. The optimized reaction conditions, including temperature, urea concentration, and concentration of reaction-enhancing additives, resulted in a 55% increase in mRNA yield with a 33% reduction in truncated mRNA. Additionally, the feasibility of a segmented flow approach allowed for high-throughput screening (HTS), enabling the production of 20 vaccine candidates within a short time frame, representing a 10-fold increase in productivity, compared to nonsegmented reactions limited by the residence time in the plug flow reactor. The findings presented for the first time here contribute to the development of a fully continuous and efficient manufacturing process for mRNA and other cell and gene therapy drugs/vaccine candidates as presented in our previous work, which discussed the integration of process analytical technologies and predictive process models in a Biopharma 4.0 facility to enable the production of clinical and large-scale doses, ensuring a rapid and resilient supply of critical therapeutics. The results in this study especially highlight that the same machine and equipment can be used for screening and manufacturing different drug candidates in continuous operation. By streamlining production and adhering to quality standards, this approach enhances the industry's ability to respond swiftly to pandemics and public health emergencies, addressing the urgent need for accessible and effective vaccines.
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Affiliation(s)
- Alina Hengelbrock
- Institute for Separation
and Process Technology, Clausthal University
of Technology, Clausthal-Zellerfeld 38678, Germany
| | - Axel Schmidt
- Institute for Separation
and Process Technology, Clausthal University
of Technology, Clausthal-Zellerfeld 38678, Germany
| | - Jochen Strube
- Institute for Separation
and Process Technology, Clausthal University
of Technology, Clausthal-Zellerfeld 38678, Germany
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23
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Purhonen J, Hofer A, Kallijärvi J. Quantification of all 12 canonical ribonucleotides by real-time fluorogenic in vitro transcription. Nucleic Acids Res 2024; 52:e6. [PMID: 38008466 PMCID: PMC10783517 DOI: 10.1093/nar/gkad1091] [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: 06/01/2023] [Revised: 10/17/2023] [Accepted: 10/30/2023] [Indexed: 11/28/2023] Open
Abstract
Enzymatic methods to quantify deoxyribonucleoside triphosphates have existed for decades. In contrast, no general enzymatic method to quantify ribonucleoside triphosphates (rNTPs), which drive almost all cellular processes and serve as precursors of RNA, exists to date. ATP can be measured with an enzymatic luminometric method employing firefly luciferase, but the quantification of other ribonucleoside mono-, di-, and triphosphates is still a challenge for a non-specialized laboratory and practically impossible without chromatography equipment. To allow feasible quantification of ribonucleoside phosphates in any laboratory with typical molecular biology and biochemistry tools, we developed a robust microplate assay based on real-time detection of the Broccoli RNA aptamer during in vitro transcription. The assay employs the bacteriophage T7 and SP6 RNA polymerases, two oligonucleotide templates encoding the 49-nucleotide Broccoli aptamer, and a high-affinity fluorogenic aptamer-binding dye to quantify each of the four canonical rNTPs. The inclusion of nucleoside mono- and diphosphate kinases in the assay reactions enabled the quantification of the mono- and diphosphate counterparts. The assay is inherently specific and tolerates concentrated tissue and cell extracts. In summary, we describe the first chromatography-free method to quantify ATP, ADP, AMP, GTP, GDP, GMP, UTP, UDP, UMP, CTP, CDP and CMP in biological samples.
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Affiliation(s)
- Janne Purhonen
- Folkhälsan Research Center, Helsinki 00290, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki 00014, Finland
| | - Anders Hofer
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå 90187, Sweden
| | - Jukka Kallijärvi
- Folkhälsan Research Center, Helsinki 00290, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki 00014, Finland
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24
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Tidwell ED, Kilde IR, Leskaj S, Koutmos M. Fluorescent Ligand Equilibrium Displacement: A High-Throughput Method for Identification of FMN Riboswitch-Binding Small Molecules. Int J Mol Sci 2024; 25:735. [PMID: 38255809 PMCID: PMC11154562 DOI: 10.3390/ijms25020735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/24/2024] Open
Abstract
Antibiotic resistance remains a pressing global concern, with most antibiotics targeting the bacterial ribosome or a limited range of proteins. One class of underexplored antibiotic targets is bacterial riboswitches, structured RNA elements that regulate key biosynthetic pathways by binding a specific ligand. We developed a methodology termed Fluorescent Ligand Equilibrium Displacement (FLED) to rapidly discover small molecules that bind the flavin mononucleotide (FMN) riboswitch. FLED leverages intrinsically fluorescent FMN and the quenching effect on RNA binding to create a label-free, in vitro method to identify compounds that can bind the apo population of riboswitch in a system at equilibrium. The response difference between known riboswitch ligands and controls demonstrates the robustness of the method for high-throughput screening. An existing drug discovery library that was screened using FLED resulted in a final hit rate of 0.67%. The concentration response of each hit was determined and revealed a variety of approximate effective concentration values. Our preliminary screening data support the use of FLED to identify small molecules for medicinal chemistry development as FMN riboswitch-targeted antibiotic compounds. This robust, label-free, and cell-free method offers a strong alternative to other riboswitch screening methods and can be adapted to a variety of laboratory setups.
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Affiliation(s)
| | - Ingrid R. Kilde
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Suada Leskaj
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Markos Koutmos
- Program in Biophysics, University of Michigan, Ann Arbor, MI 48109, USA;
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, USA;
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA;
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25
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Sapkota K, Lucas JK, Faulkner JW, Lichte MF, Guo YL, Burke DH, Huang F. Post-transcriptional capping generates coenzyme A-linked RNA. RNA Biol 2024; 21:1-12. [PMID: 38032240 PMCID: PMC10761072 DOI: 10.1080/15476286.2023.2288740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2023] [Indexed: 12/01/2023] Open
Abstract
NAD can be inserted co-transcriptionally via non-canonical initiation to form NAD-RNA. However, that mechanism is unlikely for CoA-linked RNAs due to low intracellular concentration of the required initiator nucleotide, 3'-dephospho-CoA (dpCoA). We report here that phosphopantetheine adenylyltransferase (PPAT), an enzyme of CoA biosynthetic pathway, accepts RNA transcripts as its acceptor substrate and transfers 4'-phosphopantetheine to yield CoA-RNA post-transcriptionally. Synthetic natural (RNAI) and small artificial RNAs were used to identify the features of RNA that are needed for it to serve as PPAT substrate. RNAs with 4-10 unpaired nucleotides at the 5' terminus served as PPAT substrates, but RNAs having <4 unpaired nucleotides did not undergo capping. No capping was observed when the +1A was changed to G or when 5' triphosphate was removed by RNA pyrophosphohydrolase (RppH), suggesting the enzyme recognizes pppA-RNA as an ATP analog. PPAT binding affinities were equivalent for transcripts with +1A, +1 G, or 5'OH (+1A), indicating that productive enzymatic recognition is driven more by local positioning effects than by overall binding affinity. Capping rates were independent of the number of unpaired nucleotides in the range of 4-10 nucleotides. Capping was strongly inhibited by ATP, reducing CoA-RNA production ~70% when equimolar ATP and substrate RNA were present. Dual bacterial expression of candidate RNAs with different 5' structures followed by CoA-RNA CaptureSeq revealed 12-fold enrichment of the better PPAT substrate, consistent with in vivo CoA-capping of RNA transcripts by PPAT. These results suggest post-transcriptional RNA capping as a possible mechanism for the biogenesis of CoA-RNAs in bacteria.
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Affiliation(s)
- Krishna Sapkota
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, USA
| | - Jordyn K. Lucas
- Department of Biochemistry, University of Missouri, Columbia, MO, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Jarrett W. Faulkner
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, USA
| | - Matt F. Lichte
- Department of Biochemistry, University of Missouri, Columbia, MO, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Yan-Lin Guo
- Department of Cell and Molecular Biology, University of Southern Mississippi, Hattiesburg, MS, USA
| | - Donald H. Burke
- Department of Biochemistry, University of Missouri, Columbia, MO, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
- Department of Molecular Microbiology & Immunology, University of Missouri, Columbia, MO, USA
| | - Faqing Huang
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, USA
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26
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Schmid A. Regulatory Considerations for Producing mRNA Vaccines for Clinical Trials. Methods Mol Biol 2024; 2786:321-337. [PMID: 38814402 DOI: 10.1007/978-1-0716-3770-8_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
The approval of clinical trials by the competent authorities requires comprehensive quality documentation on the new drug to be used on the clinical trial participant. In the EU, quality data is summarized as investigational medicinal product dossier (IMPD), in the United States, as investigational new drug (IND) application. For that, several preconditions concerning production, quality control, and assurance have to be fulfilled. Here, specific requirements related to mRNA vaccines are addressed on the basis of European standards.
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27
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Haslecker R, Pham VV, Glänzer D, Kreutz C, Dayie TK, D'Souza VM. Extending the toolbox for RNA biology with SegModTeX: a polymerase-driven method for site-specific and segmental labeling of RNA. Nat Commun 2023; 14:8422. [PMID: 38110450 PMCID: PMC10728113 DOI: 10.1038/s41467-023-44254-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 12/06/2023] [Indexed: 12/20/2023] Open
Abstract
RNA performs a wide range of functions regulated by its structure, dynamics, and often post-transcriptional modifications. While NMR is the leading method for understanding RNA structure and dynamics, it is currently limited by the inability to reduce spectral crowding by efficient segmental labeling. Furthermore, because of the challenging nature of RNA chemistry, the tools being developed to introduce site-specific modifications are increasingly complex and laborious. Here we use a previously designed Tgo DNA polymerase mutant to present SegModTeX - a versatile, one-pot, copy-and-paste approach to address these challenges. By precise, stepwise construction of a diverse set of RNA molecules, we demonstrate the technique to be superior to RNA polymerase driven and ligation methods owing to its substantially high yield, fidelity, and selectivity. We also show the technique to be useful for incorporating some fluorescent- and a wide range of other probes, which significantly extends the toolbox of RNA biology in general.
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Affiliation(s)
- Raphael Haslecker
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Vincent V Pham
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, 02138, USA
| | - David Glänzer
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Theodore Kwaku Dayie
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20782, USA
| | - Victoria M D'Souza
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, 02138, USA.
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28
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Song DY, Park YJ, Kim DM. A one-pot transcriptional assay method that detects the tumor biomarker FEN1 based on its flap cleavage activity. Anal Chim Acta 2023; 1282:341928. [PMID: 37923413 DOI: 10.1016/j.aca.2023.341928] [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: 09/06/2023] [Revised: 10/13/2023] [Accepted: 10/16/2023] [Indexed: 11/07/2023]
Abstract
BACKGROUND Detection of tumor biomarkers in body fluids is a significant advancement in cancer treatment because it allows diagnosis without invasive tissue biopsies. Nucleases have long been regarded as a potential class of biomarkers that can indicate the occurrence and progression of cancers. Among these, flap endonuclease 1 (FEN1) plays an important role in DNA replication and repair, and also overexpressed in abnormally proliferating cells such as cancer cells. FEN1 is thus considered to be a potential biomarker as well as a target for cancer therapy. RESULTS We developed a novel method for detecting FEN1 based on its specific endonuclease activity which incises bifurcated nucleic acids (flaps), in combination with in vitro transcription. Developed method uses a simple DNA structure (substrate DNA) carrying a short 5'-flap sequence, and a single-stranded sensor DNA encoding the Broccoli light-up aptamer. When the assay mixture was supplied with a FEN1-containing sample, the flap sequence encoding the sense sequence of T7 promoter was cleaved and released from the substrate DNA. Because the sensor DNA was designed to carry the Broccoli RNA aptamer under the antisense sequence of T7 promoter, hybridization of the excised flap onto the sensor DNA initiated the transcription of the Broccoli RNA aptamer, enabling determination of the FEN1 titer based on the fluorescence of transcribed Broccoli aptamer. By using a combination of FEN1-mediated generation of a short oligonucleotide and subsequent oligonucleotide-dependent in vitro transcription, this method could detect FEN1 in biological samples within 1 h. SIGNIFICANCE AND NOVELTY Developed method enables the detection of FEN1 by a simple one-pot reaction. It can detect sub-nanomolar concentrations of FEN1 within an hour, and has the potential to be used for cancer diagnosis, prognosis, and drug screening. It also enables easy identification of compounds that inhibit FEN1 activity and is thus a versatile platform for screening anti-cancer drugs. We anticipate that the basic principles of this assay can be applied to detect other biomolecules, such as nucleic acids.
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Affiliation(s)
- Dong-Yeon Song
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, 34134, South Korea
| | - Yu Jin Park
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, 34134, South Korea
| | - Dong-Myung Kim
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, 34134, South Korea.
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29
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Stein EM, Wang S, Dailey KG, Gravel CM, Wang S, Olejniczak M, Berry KE. Biochemical and genetic dissection of the RNA-binding surface of the FinO domain of Escherichia coli ProQ. RNA (NEW YORK, N.Y.) 2023; 29:1772-1791. [PMID: 37607742 PMCID: PMC10578477 DOI: 10.1261/rna.079697.123] [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: 04/25/2023] [Accepted: 08/03/2023] [Indexed: 08/24/2023]
Abstract
RNA-binding proteins play important roles in bacterial gene regulation through interactions with both coding and noncoding RNAs. ProQ is a FinO-domain protein that binds a large set of RNAs in Escherichia coli, though the details of how ProQ binds these RNAs remain unclear. In this study, we used a combination of in vivo and in vitro binding assays to confirm key structural features of E. coli ProQ's FinO domain and explore its mechanism of RNA interactions. Using a bacterial three-hybrid assay, we performed forward genetic screens to confirm the importance of the concave face of ProQ in RNA binding. Using gel shift assays, we directly probed the contributions of ten amino acids on ProQ binding to seven RNA targets. Certain residues (R58, Y70, and R80) were found to be essential for binding of all seven RNAs, while substitutions of other residues (K54 and R62) caused more moderate binding defects. Interestingly, substitutions of two amino acids (K35, R69), which are evolutionarily variable but adjacent to conserved residues, showed varied effects on the binding of different RNAs; these may arise from the differing sequence context around each RNA's terminator hairpin. Together, this work confirms many of the essential RNA-binding residues in ProQ initially identified in vivo and supports a model in which residues on the conserved concave face of the FinO domain such as R58, Y70, and R80 form the main RNA-binding site of E. coli ProQ, while additional contacts contribute to the binding of certain RNAs.
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Affiliation(s)
- Ewa M Stein
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Suxuan Wang
- Program in Biochemistry, Mount Holyoke College, South Hadley, Massachusetts 01075, USA
| | - Katherine G Dailey
- Program in Biochemistry, Mount Holyoke College, South Hadley, Massachusetts 01075, USA
| | - Chandra M Gravel
- Program in Biochemistry, Mount Holyoke College, South Hadley, Massachusetts 01075, USA
- Department of Chemistry, Mount Holyoke College, South Hadley, Massachusetts 01075, USA
| | - Shiying Wang
- Program in Biochemistry, Mount Holyoke College, South Hadley, Massachusetts 01075, USA
| | - Mikołaj Olejniczak
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Katherine E Berry
- Program in Biochemistry, Mount Holyoke College, South Hadley, Massachusetts 01075, USA
- Department of Chemistry, Mount Holyoke College, South Hadley, Massachusetts 01075, USA
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30
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McKenney KM, Connacher RP, Dunshee EB, Goldstrohm AC. Chemi-Northern: a versatile chemiluminescent northern blot method for analysis and quantitation of RNA molecules. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.10.561763. [PMID: 37873431 PMCID: PMC10592733 DOI: 10.1101/2023.10.10.561763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
This report describes a chemiluminescence-based detection method for RNAs on northern blots, designated Chemi-Northern. This approach builds on the simplicity and versatility of northern blotting, while dispensing of the need for expensive and cumbersome radioactivity. RNAs are first separated on denaturing gel electrophoresis, transferred to a nylon membrane, and then hybridized to a biotinylated RNA or DNA antisense probe. Streptavidin conjugated with horseradish peroxidase and enhanced chemiluminescence substrate are then used to detect the probe bound to the target RNA. Our results demonstrate the versatility of this method in detecting natural and engineered RNAs expressed in cells, including messenger and noncoding RNAs. We show that Chemi-Northern detection is sensitive and fast, detecting attomole amounts of RNA in as little as 1 second, with high signal intensity and low background. The dynamic response displays excellent linearity. Using Chemi-Northern, we measure the significant, reproducible reduction of mRNA levels by human sequence-specific RNA-binding proteins, PUM1 and PUM2. Additionally, we measure the interaction of endogenous poly(A) binding protein, PABPC1, with poly-adenylated mRNA. Thus, the Chemi-Northern method provides a versatile, simple, cost-effective method to enable researchers to detect and measure changes in RNA expression, processing, binding, and decay of RNAs.
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Affiliation(s)
- Katherine M. McKenney
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Robert P. Connacher
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Elise B. Dunshee
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Aaron C. Goldstrohm
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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31
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Martínez J, Lampaya V, Larraga A, Magallón H, Casabona D. Purification of linearized template plasmid DNA decreases double-stranded RNA formation during IVT reaction. Front Mol Biosci 2023; 10:1248511. [PMID: 37842641 PMCID: PMC10570549 DOI: 10.3389/fmolb.2023.1248511] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/19/2023] [Indexed: 10/17/2023] Open
Abstract
After the COVID-19 pandemic, messenger RNA (mRNA) has revolutionized traditional vaccine manufacturing. With the increasing number of RNA-based therapeutics, valuable new scientific insights into these molecules have emerged. One fascinating area of study is the formation of double-stranded RNA (dsRNA) during in vitro transcription (IVT) which is considered a significant impurity, as it has been identified as a major trigger in the cellular immune response pathway. Therefore, there is a growing importance placed to develop and optimize purification processes for the removal of this by-product. Traditionally, efforts have primarily focused on mRNA purification after IVT through chromatographic separations, with anion exchange and reverse phase chromatography emerging as effective tools for this purpose. However, to the best of our knowledge, the influence and significance of the quality of the linearized plasmid have not been thoroughly investigated. Plasmids production involves the growth of bacterial cultures, bacterial harvesting and lysis, and multiple filtration steps for plasmid DNA purification. The inherent complexity of these molecules, along with the multitude of purification steps involved in their processing, including the subsequent linearization and the less-developed purification techniques for linearized plasmids, often result in inconsistent batches with limited control over by-products such as dsRNA. This study aims to demonstrate how the purification process employed for linearized plasmids can impact the formation of dsRNA. Several techniques for the purification of linearized plasmids based on both, resin filtration and chromatographic separations, have been studied. As a result of that, we have optimized a chromatographic method for purifying linearized plasmids using monolithic columns with C4 chemistry (butyl chains located in the surface of the particles), which has proven successful for mRNAs of various sizes. This chromatographic separation facilitates the generation of homogeneous linearized plasmids, leading to mRNA batches with lower levels of dsRNA during subsequent IVT processes. This finding reveals that dsRNA formation is influenced not only by RNA polymerase and IVT conditions but also by the quality of the linearized template. The results suggest that plasmid impurities may contribute to the production of dsRNA by providing additional templates that can be transcribed into sequences that anneal with the mRNA molecules. This highlights the importance of considering the quality of plasmid purification in relation to dsRNA generation during transcription. Further investigation is needed to fully understand the mechanisms and implications of plasmid-derived dsRNA. This discovery could shift the focus in mRNA vaccine production, placing more emphasis on the purification of linearized plasmids and potentially saving, in some instances, a purification step for mRNA following IVT.
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Affiliation(s)
| | | | | | | | - Diego Casabona
- RNA Synthesis and Development Department, Certest Pharma, Certest Biotec, Zaragoza, Spain
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32
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Dörrenhaus R, Wagner PK, Kath-Schorr S. Two are not enough: synthetic strategies and applications of unnatural base pairs. Biol Chem 2023; 404:883-896. [PMID: 37354104 DOI: 10.1515/hsz-2023-0169] [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: 03/29/2023] [Accepted: 06/05/2023] [Indexed: 06/26/2023]
Abstract
Nucleic acid chemistry is a rapidly evolving field, and the need for novel nucleotide modifications and artificial nucleotide building blocks for diagnostic and therapeutic use, material science or for studying cellular processes continues unabated. This review focusses on the development and application of unnatural base pairs as part of an expanded genetic alphabet. Not only recent developments in "nature-like" artificial base pairs are presented, but also current synthetic methods to get access to C-glycosidic nucleotides. Wide-ranging viability in synthesis is a prerequisite for the successful use of unnatural base pairs in a broader spectrum and will be discussed.
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33
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Mao G, Srivastava AS, Wu S, Kosek D, Kirsebom LA. Importance of residue 248 in Escherichia coli RNase P RNA mediated cleavage. Sci Rep 2023; 13:14140. [PMID: 37644068 PMCID: PMC10465520 DOI: 10.1038/s41598-023-41203-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 08/23/2023] [Indexed: 08/31/2023] Open
Abstract
tRNA genes are transcribed as precursors and RNase P generates the matured 5' end of tRNAs. It has been suggested that residue - 1 (the residue immediately 5' of the scissile bond) in the pre-tRNA interacts with the well-conserved bacterial RNase P RNA (RPR) residue A248 (Escherichia coli numbering). The way A248 interacts with residue - 1 is not clear. To gain insight into the role of A248, we analyzed cleavage as a function of A248 substitutions and N-1 nucleobase identity by using pre-tRNA and three model substrates. Our findings are consistent with a model where the structural topology of the active site varies and depends on the identity of the nucleobases at, and in proximity to, the cleavage site and their potential to interact. This leads to positioning of Mg2+ that activates the water that acts as the nucleophile resulting in efficient and correct cleavage. We propose that in addition to be involved in anchoring the substrate the role of A248 is to exclude bulk water from access to the amino acid acceptor stem, thereby preventing non-specific hydrolysis of the pre-tRNA. Finally, base stacking is discussed as a way to protect functionally important base-pairing interactions from non-specific hydrolysis, thereby ensuring high fidelity during RNA processing and the decoding of mRNA.
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Affiliation(s)
- Guanzhong Mao
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, 751 24, Uppsala, Sweden
| | - Abhishek S Srivastava
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, 751 24, Uppsala, Sweden
| | - Shiying Wu
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, 751 24, Uppsala, Sweden
| | - David Kosek
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, 751 24, Uppsala, Sweden
| | - Leif A Kirsebom
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, 751 24, Uppsala, Sweden.
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34
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Banna HA, Das NK, Ojha M, Koirala D. Advances in chaperone-assisted RNA crystallography using synthetic antibodies. BBA ADVANCES 2023; 4:100101. [PMID: 37655005 PMCID: PMC10466895 DOI: 10.1016/j.bbadva.2023.100101] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/13/2023] [Accepted: 08/17/2023] [Indexed: 09/02/2023] Open
Abstract
RNA molecules play essential roles in many biological functions, from gene expression regulation, cellular growth, and metabolism to catalysis. They frequently fold into three-dimensional structures to perform their functions. Therefore, determining RNA structure represents a key step for understanding the structure-function relationships and developing RNA-targeted therapeutics. X-ray crystallography remains a method of choice for determining high-resolution RNA structures, but it has been challenging due to difficulties associated with RNA crystallization and phasing. Several natural and synthetic RNA binding proteins have been used to facilitate RNA crystallography. Having unique properties to help crystal packing and phasing, synthetic antibody fragments, specifically the Fabs, have emerged as promising RNA crystallization chaperones, and so far, over a dozen of RNA structures have been solved using this strategy. Nevertheless, multiple steps in this approach need to be improved, including the recombinant expression of these anti-RNA Fabs, to warrant the full potential of these synthetic Fabs as RNA crystallization chaperones. This review highlights the nuts and bolts and recent advances in the chaperone-assisted RNA crystallography approach, specifically emphasizing the Fab antibody fragments as RNA crystallization chaperones.
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Affiliation(s)
- Hasan Al Banna
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Naba Krishna Das
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Manju Ojha
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Deepak Koirala
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
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35
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Zhou W, Jiang L, Liao S, Wu F, Yang G, Hou L, Liu L, Pan X, Jia W, Zhang Y. Vaccines' New Era-RNA Vaccine. Viruses 2023; 15:1760. [PMID: 37632102 PMCID: PMC10458896 DOI: 10.3390/v15081760] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/15/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
RNA vaccines, including conventional messenger RNA (mRNA) vaccines, circular RNA (circRNA) vaccines, and self-amplifying RNA (saRNA) vaccines, have ushered in a promising future and revolutionized vaccine development. The success of mRNA vaccines in combating the COVID-19 pandemic caused by the SARS-CoV-2 virus that emerged in 2019 has highlighted the potential of RNA vaccines. These vaccines possess several advantages, such as high efficacy, adaptability, simplicity in antigen design, and the ability to induce both humoral and cellular immunity. They also offer rapid and cost-effective manufacturing, flexibility to target emerging or mutant pathogens and a potential approach for clearing immunotolerant microbes by targeting bacterial or parasitic survival mechanisms. The self-adjuvant effect of mRNA-lipid nanoparticle (LNP) formulations or circular RNA further enhances the potential of RNA vaccines. However, some challenges need to be addressed. These include the technology's immaturity, high research expenses, limited duration of antibody response, mRNA instability, low efficiency of circRNA cyclization, and the production of double-stranded RNA as a side product. These factors hinder the widespread adoption and utilization of RNA vaccines, particularly in developing countries. This review provides a comprehensive overview of mRNA, circRNA, and saRNA vaccines for infectious diseases while also discussing their development, current applications, and challenges.
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Affiliation(s)
- Wenshuo Zhou
- CNBG-Virogin Biotech (Shanghai) Co., Ltd., Shanghai 201800, China; (W.Z.); (L.J.); (S.L.); (F.W.); (G.Y.); (L.H.); (L.L.); (X.P.); (W.J.)
| | - Linglei Jiang
- CNBG-Virogin Biotech (Shanghai) Co., Ltd., Shanghai 201800, China; (W.Z.); (L.J.); (S.L.); (F.W.); (G.Y.); (L.H.); (L.L.); (X.P.); (W.J.)
| | - Shimiao Liao
- CNBG-Virogin Biotech (Shanghai) Co., Ltd., Shanghai 201800, China; (W.Z.); (L.J.); (S.L.); (F.W.); (G.Y.); (L.H.); (L.L.); (X.P.); (W.J.)
| | - Feifei Wu
- CNBG-Virogin Biotech (Shanghai) Co., Ltd., Shanghai 201800, China; (W.Z.); (L.J.); (S.L.); (F.W.); (G.Y.); (L.H.); (L.L.); (X.P.); (W.J.)
| | - Guohuan Yang
- CNBG-Virogin Biotech (Shanghai) Co., Ltd., Shanghai 201800, China; (W.Z.); (L.J.); (S.L.); (F.W.); (G.Y.); (L.H.); (L.L.); (X.P.); (W.J.)
| | - Li Hou
- CNBG-Virogin Biotech (Shanghai) Co., Ltd., Shanghai 201800, China; (W.Z.); (L.J.); (S.L.); (F.W.); (G.Y.); (L.H.); (L.L.); (X.P.); (W.J.)
| | - Lan Liu
- CNBG-Virogin Biotech (Shanghai) Co., Ltd., Shanghai 201800, China; (W.Z.); (L.J.); (S.L.); (F.W.); (G.Y.); (L.H.); (L.L.); (X.P.); (W.J.)
| | - Xinping Pan
- CNBG-Virogin Biotech (Shanghai) Co., Ltd., Shanghai 201800, China; (W.Z.); (L.J.); (S.L.); (F.W.); (G.Y.); (L.H.); (L.L.); (X.P.); (W.J.)
| | - William Jia
- CNBG-Virogin Biotech (Shanghai) Co., Ltd., Shanghai 201800, China; (W.Z.); (L.J.); (S.L.); (F.W.); (G.Y.); (L.H.); (L.L.); (X.P.); (W.J.)
- Shanghai-Virogin Biotech Co., Ltd., Shanghai 201800, China
| | - Yuntao Zhang
- CNBG-Virogin Biotech (Shanghai) Co., Ltd., Shanghai 201800, China; (W.Z.); (L.J.); (S.L.); (F.W.); (G.Y.); (L.H.); (L.L.); (X.P.); (W.J.)
- Sinopharm Group China National Biotech Group (CNBG) Co., Ltd., Beijing 100124, China
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36
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Kang DD, Li H, Dong Y. Advancements of in vitro transcribed mRNA (IVT mRNA) to enable translation into the clinics. Adv Drug Deliv Rev 2023; 199:114961. [PMID: 37321375 PMCID: PMC10264168 DOI: 10.1016/j.addr.2023.114961] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 06/02/2023] [Accepted: 06/08/2023] [Indexed: 06/17/2023]
Abstract
The accelerated progress and approval of two mRNA-based vaccines to address the SARS-CoV-2 virus were unprecedented. This record-setting feat was made possible through the solid foundation of research on in vitro transcribed mRNA (IVT mRNA) which could be utilized as a therapeutic modality. Through decades of thorough research to overcome barriers to implementation, mRNA-based vaccines or therapeutics offer many advantages to rapidly address a broad range of applications including infectious diseases, cancers, and gene editing. Here, we describe the advances that have supported the adoption of IVT mRNA in the clinics, including optimization of the IVT mRNA structural components, synthesis, and lastly concluding with different classes of IVT RNA. Continuing interest in driving IVT mRNA technology will enable a safer and more efficacious therapeutic modality to address emerging and existing diseases.
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Affiliation(s)
- Diana D Kang
- Division of Pharmaceutics & Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States; Genomics Institute, Precision Immunology Institute, Department of Oncological Sciences, Tisch Cancer Institute, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Haoyuan Li
- Genomics Institute, Precision Immunology Institute, Department of Oncological Sciences, Tisch Cancer Institute, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Yizhou Dong
- Division of Pharmaceutics & Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States; Department of Biomedical Engineering, The Center for Clinical and Translational Science, The Comprehensive Cancer Center; Dorothy M. Davis Heart & Lung Research Institute, Department of Radiation Oncology, The Ohio State University, Columbus, OH 43210, United States; Genomics Institute, Precision Immunology Institute, Department of Oncological Sciences, Tisch Cancer Institute, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
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37
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Malagoda Pathiranage K, Martin CT. A simple approach to improving RNA synthesis: Salt inhibition of RNA rebinding coupled with strengthening promoter binding by a targeted gap in the DNA. Methods Enzymol 2023; 691:209-222. [PMID: 37914447 DOI: 10.1016/bs.mie.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
T7 RNA polymerase is widely used to synthesize RNA of any length, and long-standing protocols exist to efficiently generate large amounts of RNA. Such synthesis, however, is often plagued by so-called "nontemplated additions" at the 3' end, which are in fact templated by the RNA itself and give rise to double-stranded RNA impurities in RNA therapeutics. These additions are generated by RNA polymerase rebinding to the product RNA (independent of DNA) and this rebinding is in competition with promoter binding. This chapter reports on a general approach that simultaneously weakens RNA rebinding by increasing salt, while at the same time increases promoter binding through manipulating the promoter DNA structure, shifting the balance away from self-primed extension. We present two approaches for use in different regimes. For (short) RNAs using synthetic oligonucleotides as DNA, promoter binding is strengthened by using a partially single stranded promoter construct already in wide use in the field. For the synthesis of RNA (of any length), one can replicate the behavior of the first approach by introducing a targeted gap in the promoter, using a PCR primer containing an engineered deoxyuracil that is then excised by a commercially available enzyme system, to leave a promoter-strengthening gap. Both approaches are simple to implement, with only slight variations on standard synthesis approaches, making them valuable tools for a wide range of applications, from basic science to mRNA, CRISPR, lncRNA, and other therapeutics.
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Affiliation(s)
| | - Craig T Martin
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA, United States.
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38
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Kumar A, Daripa P, Maiti S, Jain N. Interaction of hnRNPB1 with Helix-12 of hHOTAIR Reveals the Distinctive Mode of RNA Recognition That Enables the Structural Rearrangement by LCD. Biochemistry 2023; 62:2041-2054. [PMID: 37307069 DOI: 10.1021/acs.biochem.3c00181] [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: 06/13/2023]
Abstract
The lncRNA human Hox transcript antisense intergenic RNA (hHOTAIR) regulates gene expression by recruiting chromatin modifiers. The prevailing model suggests that hHOTAIR recruits hnRNPB1 to facilitate intermolecular RNA-RNA interactions between the lncRNA HOTAIR and its target gene transcripts. This B1-mediated RNA-RNA interaction modulates the structure of hHOTAIR, attenuates its inhibitory effect on polycomb repression complex 2, and enhances its methyl transferase activity. However, the molecular details by which the nuclear hnRNPB1 protein assembles on the lncRNA HOTAIR have not yet been described. Here, we investigate the molecular interactions between hnRNPB1 and Helix-12 (hHOTAIR). We show that the low-complexity domain segment (LCD) of hnRNPB1 interacts with a strong affinity for Helix-12. Our studies revealed that unbound Helix-12 folds into a specific base-pairing pattern and contains an internal loop that, as determined by thermal melting and NMR studies, exhibits hydrogen bonding between strands and forms the recognition site for the LCD segment. In addition, mutation studies show that the secondary structure of Helix-12 makes an important contribution by acting as a landing pad for hnRNPB1. The secondary structure of Helix-12 is involved in specific interactions with different domains of hnRNPB1. Finally, we show that the LCD unwinds Helix-12 locally, indicating its importance in the hHOTAIR restructuring mechanism.
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Affiliation(s)
- Ajit Kumar
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Purba Daripa
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India
| | - Souvik Maiti
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Niyati Jain
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India
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39
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Luo D, Wu Z, Wang D, Zhang J, Shao F, Wang S, Cestellos-Blanco S, Xu D, Cao Y. Lateral flow immunoassay for rapid and sensitive detection of dsRNA contaminants in in vitro-transcribed mRNA products. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 32:445-453. [PMID: 37181450 PMCID: PMC10173069 DOI: 10.1016/j.omtn.2023.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 04/04/2023] [Indexed: 05/16/2023]
Abstract
High purity is essential in mRNA-based therapeutic applications. A major contaminant of in vitro-transcribed (IVT) mRNA manufacturing is double-stranded RNA (dsRNA), which can induce severe anti-viral immune responses. Detection methods, such as agarose gel electrophoresis, ELISA, and dot-blot assay, are used to detect the existence of dsRNA in IVT mRNA products. However, these methods are either not sensitive enough or time-consuming. To overcome these challenges, we develop a rapid, sensitive, and easy-to-implement colloidal gold nanoparticle-based lateral flow strip assay (LFSA) with sandwich format for the detection of dsRNA from IVT process. dsRNA contaminant can be determined visually on the test strip or quantitatively with a portable optical detector. This method allows for a 15 min detection of N1-methyl-pseudouridine (m1Ψ)-containing dsRNA with a detection limit of 69.32 ng/mL. Furthermore, we establish the correlation between the LFSA test results and the immune response caused by dsRNA in mice. The LFSA platform allows the rapid, sensitive, and quantitative monitoring of purity in massive IVT mRNA products and aids for the prevention of immunogenicity by dsRNA impurities.
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Affiliation(s)
- Dengwang Luo
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhanfeng Wu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Daming Wang
- Academy for Engineering and Technology, Fudan University, Shanghai 200433, China
- Suzhou Institute of Biomedical Engineering and Technology (SIBET), Chinese Academy of Sciences, Suzhou, Jiangsu 215163, China
- Anbio Biotechnology Company, Xiamen, Fujian 361026, China
| | - Jieli Zhang
- Anbio Biotechnology Company, Xiamen, Fujian 361026, China
| | - Fei Shao
- University of Chinese Academy of Sciences, Beijing 100049, China
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shuo Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Stefano Cestellos-Blanco
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Dawei Xu
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China
- Corresponding author: Dawei Xu, CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China.
| | - Yuhong Cao
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China
- School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing 100049, China
- Corresponding author: Yuhong Cao, CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China.
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40
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Stein EM, Wang S, Dailey K, Gravel CM, Wang S, Olejniczak M, Berry KE. Biochemical and genetic dissection of the RNA-binding surface of the FinO domain of Escherichia coli ProQ. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.25.538249. [PMID: 37163069 PMCID: PMC10168233 DOI: 10.1101/2023.04.25.538249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
RNA-binding proteins play important roles in bacterial gene regulation through interactions with both coding and non-coding RNAs. ProQ is a FinO-domain protein that binds a large set of RNAs in Escherichia coli , though the details of how ProQ binds these RNAs remain unclear. In this study, we used a combination of in vivo and in vitro binding assays to confirm key structural features of E. coli ProQ's FinO domain and explore its mechanism of RNA interactions. Using a bacterial three-hybrid assay, we performed forward genetic screens to confirm the importance of the concave face of ProQ in RNA binding. Using gel shift assays, we directly probed the contributions of ten amino acids on ProQ binding to seven RNA targets. Certain residues (R58, Y70, and R80) were found to be essential for binding of all seven RNAs, while substitutions of other residues (K54 and R62) caused more moderate binding defects. Interestingly, substitutions of two amino acids (K35, R69), which are evolutionarily variable but adjacent to conserved residues, showed varied effects on the binding of different RNAs; these may arise from the differing sequence context around each RNA's terminator hairpin. Together, this work confirms many of the essential RNA-binding residues in ProQ initially identified in vivo and supports a model in which residues on the conserved concave face of the FinO domain such as R58, Y70 and R80 form the main RNA-binding site of E. coli ProQ, while additional contacts contribute to the binding of certain RNAs.
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Affiliation(s)
- Ewa M. Stein
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
| | - Suxuan Wang
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA, 01075, USA
| | - Katherine Dailey
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA, 01075, USA
| | - Chandra M Gravel
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA, 01075, USA
- Department of Chemistry, Mount Holyoke College, South Hadley, MA, 01075, USA
| | - Shiying Wang
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA, 01075, USA
| | - Mikołaj Olejniczak
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
| | - Katherine E Berry
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA, 01075, USA
- Department of Chemistry, Mount Holyoke College, South Hadley, MA, 01075, USA
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41
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Si J, Zhou W, Fang Y, Zhou D, Gao Y, Yao Q, Shen X, Zhu C. Label-Free Detection of T4 Polynucleotide Kinase Activity and Inhibition via Malachite Green Aptamer Generated from Ligation-Triggered Transcription. BIOSENSORS 2023; 13:bios13040449. [PMID: 37185524 PMCID: PMC10135927 DOI: 10.3390/bios13040449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/28/2023] [Accepted: 03/30/2023] [Indexed: 05/17/2023]
Abstract
Polynucleotide kinase (PNK) is a key enzyme that is necessary for ligation-based DNA repair. The activity assay and inhibitor screening for PNK may contribute to the prediction and improvement of tumor treatment sensitivity, respectively. Herein, we developed a simple, low-background, and label-free method for both T4 PNK activity detection and inhibitor screening by combining a designed ligation-triggered T7 transcriptional amplification system and a crafty light-up malachite green aptamer. Moreover, this method successfully detected PNK activity in the complex biological matrix with satisfactory outcomes, indicating its great potential in clinical practice.
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Affiliation(s)
- Jingyi Si
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Wei Zhou
- Department of School and Nutrition, Shanghai Yangpu District Center for Disease Control and Prevention, Shanghai 200090, China
| | - Ying Fang
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Da Zhou
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yifan Gao
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Qunyan Yao
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Xizhong Shen
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Changfeng Zhu
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
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42
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De Capitani J, Mutschler H. The Long Road to a Synthetic Self-Replicating Central Dogma. Biochemistry 2023; 62:1221-1232. [PMID: 36944355 PMCID: PMC10077596 DOI: 10.1021/acs.biochem.3c00023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
The construction of a biochemical system capable of self-replication is a key objective in bottom-up synthetic biology. Throughout the past two decades, a rapid progression in the design of in vitro cell-free systems has provided valuable insight into the requirements for the development of a minimal system capable of self-replication. The main limitations of current systems can be attributed to their macromolecular composition and how the individual macromolecules use the small molecules necessary to drive RNA and protein synthesis. In this Perspective, we discuss the recent steps that have been taken to generate a minimal cell-free system capable of regenerating its own macromolecular components and maintaining the homeostatic balance between macromolecular biogenesis and consumption of primary building blocks. By following the flow of biological information through the central dogma, we compare the current versions of these systems to date and propose potential alterations aimed at designing a model system for self-replicative synthetic cells.
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Affiliation(s)
- Jacopo De Capitani
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
| | - Hannes Mutschler
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
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43
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Aladin V, Sreemantula AK, Biedenbänder T, Marchanka A, Corzilius B. Specific Signal Enhancement on an RNA-Protein Interface by Dynamic Nuclear Polarization. Chemistry 2023; 29:e202203443. [PMID: 36533705 DOI: 10.1002/chem.202203443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 12/18/2022] [Accepted: 12/19/2022] [Indexed: 12/23/2022]
Abstract
Sensitivity and specificity are both crucial for the efficient solid-state NMR structure determination of large biomolecules. We present an approach that features both advantages by site-specific enhancement of NMR spectroscopic signals from the protein-RNA binding site within a ribonucleoprotein (RNP) by dynamic nuclear polarization (DNP). This approach uses modern biochemical techniques for sparse isotope labeling and exploits the molecular dynamics of 13 C-labeled methyl groups exclusively present in the protein. These dynamics drive heteronuclear cross relaxation and thus allow specific hyperpolarization transfer across the biomolecular complex's interface. For the example of the L7Ae protein in complex with a 26mer guide RNA minimal construct from the box C/D complex in archaea, we demonstrate that a single methyl-nucleotide contact is responsible for most of the polarization transfer to the RNA, and that this specific transfer can be used to boost both NMR spectral sensitivity and specificity by DNP.
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Affiliation(s)
- Victoria Aladin
- Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 27, 18059, Rostock, Germany
- Department Life, Light & Matter, University of Rostock, Albert-Einstein-Str. 25, 18059, Rostock, Germany
| | - Arun K Sreemantula
- Institute for Organic Chemistry and, Centre of Biomolecular Drug Research (BMWZ), Leibniz University Hannover, Schneiderberg 38, 30167, Hannover, Germany
| | - Thomas Biedenbänder
- Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 27, 18059, Rostock, Germany
- Department Life, Light & Matter, University of Rostock, Albert-Einstein-Str. 25, 18059, Rostock, Germany
| | - Alexander Marchanka
- Institute for Organic Chemistry and, Centre of Biomolecular Drug Research (BMWZ), Leibniz University Hannover, Schneiderberg 38, 30167, Hannover, Germany
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstr. 1, 69117, Heidelberg, Germany
| | - Björn Corzilius
- Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 27, 18059, Rostock, Germany
- Department Life, Light & Matter, University of Rostock, Albert-Einstein-Str. 25, 18059, Rostock, Germany
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29, 18059, Rostock, Germany
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44
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Chien PY, Gao L, Liu Y. Quantitative Analysis of Transcription Termination via Position-Selective Labeling of RNA (PLOR) Method. Int J Mol Sci 2023; 24:ijms24054934. [PMID: 36902367 PMCID: PMC10003555 DOI: 10.3390/ijms24054934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023] Open
Abstract
T7 RNA polymerase is the most widely used enzyme in RNA synthesis, and it is also used for RNA labeling in position-selective labeling of RNA (PLOR). PLOR is a liquid-solid hybrid phase method that has been developed to introduce labels to specific positions of RNA. Here, we applied PLOR as a single-round transcription method to quantify the terminated and read-through products in transcription for the first time. Various factors, including pausing strategies, Mg2+, ligand and the NTP concentration at the transcriptional termination of adenine riboswitch RNA have been characterized. This helps to understand transcription termination, which is one of the least understood processes in transcription. Additionally, our strategy can potentially be used to study the co-transcription behavior of general RNA, especially when continuous transcription is not desired.
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45
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Yang H, Eremeeva E, Abramov M, Jacquemyn M, Groaz E, Daelemans D, Herdewijn P. CRISPR-Cas9 recognition of enzymatically synthesized base-modified nucleic acids. Nucleic Acids Res 2023; 51:1501-1511. [PMID: 36611237 PMCID: PMC9976875 DOI: 10.1093/nar/gkac1147] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/09/2022] [Accepted: 11/17/2022] [Indexed: 01/09/2023] Open
Abstract
An enzymatic method has been successfully established enabling the generation of partially base-modified RNA (previously named RZA) constructs, in which all G residues were replaced by isomorphic fluorescent thienoguanosine (thG) analogs, as well as fully modified RZA featuring thG, 5-bromocytosine, 7-deazaadenine and 5-chlorouracil. The transcriptional efficiency of emissive fully modified RZA was found to benefit from the use of various T7 RNA polymerase variants. Moreover, dthG could be incorporated into PCR products by Taq DNA polymerase together with the other three base-modified nucleotides. Notably, the obtained RNA products containing thG as well as thG together with 5-bromocytosine could function as effectively as natural sgRNAs in an in vitro CRISPR-Cas9 cleavage assay. N1-Methylpseudouridine was also demonstrated to be a faithful non-canonical substitute of uridine to direct Cas9 nuclease cleavage when incorporated in sgRNA. The Cas9 inactivation by 7-deazapurines indicated the importance of the 7-nitrogen atom of purines in both sgRNA and PAM site for achieving efficient Cas9 cleavage. Additional aspects of this study are discussed in relation to the significance of sgRNA-protein and PAM--protein interactions that were not highlighted by the Cas9-sgRNA-DNA complex crystal structure. These findings could expand the impact and therapeutic value of CRISPR-Cas9 and other RNA-based technologies.
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Affiliation(s)
- Hui Yang
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49, Box 1041, 3000 Leuven, Belgium
| | - Elena Eremeeva
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49, Box 1041, 3000 Leuven, Belgium.,Queensland University of Technology, Centre for Agriculture and the Bioeconomy, Molecular Engineering Group, George Street 2, 4000 Brisbane, Queensland, Australia
| | - Mikhail Abramov
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49, Box 1041, 3000 Leuven, Belgium
| | - Maarten Jacquemyn
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, Box 1043, 3000 Leuven, Belgium
| | - Elisabetta Groaz
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49, Box 1041, 3000 Leuven, Belgium.,University of Padova, Department of Pharmaceutical and Pharmacological Sciences, Via Marzolo 5, 35131 Padova, Italy
| | - Dirk Daelemans
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, Box 1043, 3000 Leuven, Belgium
| | - Piet Herdewijn
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49, Box 1041, 3000 Leuven, Belgium
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46
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General Strategies for RNA X-ray Crystallography. Molecules 2023; 28:molecules28052111. [PMID: 36903357 PMCID: PMC10004510 DOI: 10.3390/molecules28052111] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 02/22/2023] [Accepted: 02/22/2023] [Indexed: 02/27/2023] Open
Abstract
An extremely small proportion of the X-ray crystal structures deposited in the Protein Data Bank are of RNA or RNA-protein complexes. This is due to three main obstacles to the successful determination of RNA structure: (1) low yields of pure, properly folded RNA; (2) difficulty creating crystal contacts due to low sequence diversity; and (3) limited methods for phasing. Various approaches have been developed to address these obstacles, such as native RNA purification, engineered crystallization modules, and incorporation of proteins to assist in phasing. In this review, we will discuss these strategies and provide examples of how they are used in practice.
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47
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Yang X, Liu Y, Cui W, Liu M, Wang W. Distinct Gag interaction properties of HIV-1 RNA 5' leader conformers reveal a mechanism for dimeric genome selection. RNA (NEW YORK, N.Y.) 2023; 29:217-227. [PMID: 36384962 PMCID: PMC9891258 DOI: 10.1261/rna.079347.122] [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: 07/10/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
During HIV-1 assembly, two copies of viral genomic RNAs (gRNAs) are selectively packaged into new viral particles. This process is mediated by specific interactions between HIV-1 Gag and the packaging signals at the 5' leader (5'L) of viral gRNA. 5'L is able to adopt different conformations, which promotes either gRNA dimerization and packaging or Gag translation. Dimerization and packaging are coupled. Whether the selective packaging of the gRNA dimer is due to favorable interactions between Gag and 5'L in the packaging conformation is not known. Here, using RNAs mimicking the two 5'L conformers, we show that the 5'L conformation dramatically affects Gag-RNA interactions. Compared to the RNA in the translation conformation (5'LT), the RNA in the packaging conformation (5'LP) can bind more Gag molecules. Gag associates with 5'LP faster than it binds to 5'LT, whereas Gag dissociates from 5'LP more slowly. The Gag-5'LP complex is more stable at high salt concentrations. The NC-SP2-p6 region of Gag likely accounts for the faster association and slower dissociation kinetics for the Gag-5'LP interaction and for the higher stability. In summary, our data suggest that conformational changes play an important role in the selection of dimeric genomes, probably by affecting the binding kinetics and stability of the Gag-5'L complex.
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Affiliation(s)
- Xin Yang
- Institute of Life Sciences, Chongqing Medical University, Chongqing 400016, China
| | - Yong Liu
- Institute of Life Sciences, Chongqing Medical University, Chongqing 400016, China
| | - Wen Cui
- Institute of Life Sciences, Chongqing Medical University, Chongqing 400016, China
| | - Mengmeng Liu
- Office of Research Administration, Chongqing Medical University, Chongqing 400016, China
| | - Wei Wang
- Institute of Life Sciences, Chongqing Medical University, Chongqing 400016, China
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48
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Grzela R, Piecyk K, Stankiewicz-Drogon A, Pietrow P, Lukaszewicz M, Kurpiejewski K, Darzynkiewicz E, Jankowska-Anyszka M. N2 modified dinucleotide cap analogs as a potent tool for mRNA engineering. RNA (NEW YORK, N.Y.) 2023; 29:200-216. [PMID: 36418172 PMCID: PMC9891257 DOI: 10.1261/rna.079460.122] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
mRNA-based vaccines are relatively new technologies that have been in the field of interest of research centers and pharmaceutical companies in recent years. Such therapeutics are an attractive alternative for DNA-based vaccines since they provide material that can be used with no risk of genomic integration. Additionally, mRNA can be quite easily engineered to introduce modifications for different applications or to modulate its properties, for example, to increase translational efficiency or stability, which is not available for DNA vectors. Here, we describe the use of N2 modified dinucleotide cap analogs as components of mRNA transcripts. The compounds obtained showed very promising biological properties while incorporated into mRNA. The presented N2-guanine modifications within the cap structure ensure proper attachment of the dinucleotide to the transcripts in the IVT reaction, guarantees their incorporation only in the correct orientation, and enables highly efficient translation of mRNA both in the in vitro translation system and in human HEK293 cells.
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Affiliation(s)
- Renata Grzela
- Division of Biophysics, Institute of Experimental Physics, University of Warsaw, 02-093 Warsaw, Poland
| | - Karolina Piecyk
- Faculty of Chemistry, University of Warsaw, 02-093 Warsaw, Poland
| | - Anna Stankiewicz-Drogon
- Division of Biophysics, Institute of Experimental Physics, University of Warsaw, 02-093 Warsaw, Poland
| | - Paulina Pietrow
- Faculty of Chemistry, University of Warsaw, 02-093 Warsaw, Poland
| | - Maciej Lukaszewicz
- Division of Biophysics, Institute of Experimental Physics, University of Warsaw, 02-093 Warsaw, Poland
| | | | - Edward Darzynkiewicz
- Division of Biophysics, Institute of Experimental Physics, University of Warsaw, 02-093 Warsaw, Poland
- Center of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
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Deich C, Cash B, Sato W, Sharon J, Aufdembrink L, Gaut NJ, Heili J, Stokes K, Engelhart AE, Adamala KP. T7Max transcription system. J Biol Eng 2023; 17:4. [PMID: 36691081 PMCID: PMC9872363 DOI: 10.1186/s13036-023-00323-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 01/04/2023] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Efficient cell-free protein expression from linear DNA templates has remained a challenge primarily due to template degradation. In addition, the yields of transcription in cell-free systems lag behind transcriptional efficiency of live cells. Most commonly used in vitro translation systems utilize T7 RNA polymerase, which is also the enzyme included in many commercial kits. RESULTS Here we present characterization of a variant of T7 RNA polymerase promoter that acts to significantly increase the yields of gene expression within in vitro systems. We have demonstrated that T7Max increases the yield of translation in many types of commonly used in vitro protein expression systems. We also demonstrated increased protein expression yields from linear templates, allowing the use of T7Max driven expression from linear templates. CONCLUSIONS The modified promoter, termed T7Max, recruits standard T7 RNA polymerase, so no protein engineering is needed to take advantage of this method. This technique could be used with any T7 RNA polymerase- based in vitro protein expression system.
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Affiliation(s)
- Christopher Deich
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA
| | - Brock Cash
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA
| | - Wakana Sato
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA
| | - Judee Sharon
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA
| | - Lauren Aufdembrink
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA
| | - Nathaniel J Gaut
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA
| | - Joseph Heili
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA
| | - Kaitlin Stokes
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA
| | - Aaron E Engelhart
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA.
| | - Katarzyna P Adamala
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA.
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Shen M, Goforth JB, Eisenstein RS. Iron-dependent post transcriptional control of mitochondrial aconitase expression. Metallomics 2023; 15:mfac099. [PMID: 36702557 PMCID: PMC9902864 DOI: 10.1093/mtomcs/mfac099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 12/23/2022] [Indexed: 01/28/2023]
Abstract
Iron regulatory proteins (IRPs) control the translation of animal cell mRNAs encoding proteins with diverse roles. This includes the iron storage protein ferritin and the tricarboxylic cycle (TCA) enzyme mitochondrial aconitase (ACO2) through iron-dependent binding of IRP to the iron responsive element (IRE) in the 5' untranslated region (UTR). To further elucidate the mechanisms allowing IRPs to control translation of 5' IRE-containing mRNA differentially, we focused on Aco2 mRNA, which is weakly controlled versus the ferritins. Rat liver contains two classes of Aco2 mRNAs, with and without an IRE, due to alterations in the transcription start site. Structural analysis showed that the Aco2 IRE adopts the canonical IRE structure but lacks the dynamic internal loop/bulge five base pairs 5' of the CAGUG(U/C) terminal loop in the ferritin IREs. Unlike ferritin mRNAs, the Aco2 IRE lacks an extensive base-paired flanking region. Using a full-length Aco2 mRNA expression construct, iron controlled ACO2 expression in an IRE-dependent and IRE-independent manner, the latter of which was eliminated with the ACO23C3S mutant that cannot bind the FeS cluster. Iron regulation of ACO23C3S encoded by the full-length mRNA was completely IRE-dependent. Replacement of the Aco23C3S 5' UTR with the Fth1 IRE with base-paired flanking sequences substantially improved iron responsiveness, as did fusing of the Fth1 base-paired flanking sequences to the native IRE in the Aco3C3S construct. Our studies further define the mechanisms underlying the IRP-dependent translational regulatory hierarchy and reveal that Aco2 mRNA species lacking the IRE contribute to the expression of this TCA cycle enzyme.
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Affiliation(s)
- Macy Shen
- Department of Nutritional Sciences, University of Wisconsin-Madison, 1415 Linden Drive, Madison, WI 53706, USA
- Department of Chemistry and Biochemistry, California State University-Fullerton, Fullerton, CA 92834-6866, USA
| | - Jeremy B Goforth
- Department of Nutritional Sciences, University of Wisconsin-Madison, 1415 Linden Drive, Madison, WI 53706, USA
- Science Department, Lodi Middle School, 945 S. Ham Lane, Lodi, CA 95242, USA
| | - Richard S Eisenstein
- Department of Nutritional Sciences, University of Wisconsin-Madison, 1415 Linden Drive, Madison, WI 53706, USA
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