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Khatik SY, Roy S, Srivatsan SG. Synthesis and Enzymatic Incorporation of a Dual-App Nucleotide Probe That Reports Antibiotics-Induced Conformational Change in the Bacterial Ribosomal Decoding Site RNA. ACS Chem Biol 2024; 19:687-695. [PMID: 38407057 DOI: 10.1021/acschembio.3c00676] [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: 02/27/2024]
Abstract
Natural nucleosides are nonfluorescent and do not have intrinsic labels that can be readily utilized for analyzing nucleic acid structure and recognition. In this regard, researchers typically use the so-called "one-label, one-technique" approach to study nucleic acids. However, we envisioned that a responsive dual-app nucleoside system that harnesses the power of two complementing biophysical techniques namely, fluorescence and 19F NMR, will allow the investigation of nucleic acid conformations more comprehensively than before. We recently introduced a nucleoside analogue by tagging trifluoromethyl-benzofuran at the C5 position of 2'-deoxyuridine, which serves as an excellent fluorescent and 19F NMR probe to study G-quadruplex and i-motif structures. Taking forward, here, we report the development of a ribonucleotide version of the dual-app probe to monitor antibiotics-induced conformational changes in RNA. The ribonucleotide analog is derived by conjugating trifluoromethyl-benzofuran at the C5 position of uridine (TFBF-UTP). The analog is efficiently incorporated by T7 RNA polymerase to produce functionalized RNA transcripts. Detailed photophysical and 19F NMR of the nucleoside and nucleotide incorporated into RNA oligonucleotides revealed that the analog is structurally minimally invasive and can be used for probing RNA conformations by fluorescence and 19F NMR techniques. Using the probe, we monitored and estimated aminoglycoside antibiotics binding to the bacterial ribosomal decoding site RNA (A-site, a very important RNA target). While 2-aminopurine, a famous fluorescent nucleic acid probe, fails to detect structurally similar aminoglycoside antibiotics binding to the A-site, our probe reports the binding of different aminoglycosides to the A-site. Taken together, our results demonstrate that TFBF-UTP is a very useful addition to the nucleic acid analysis toolbox and could be used to devise discovery platforms to identify new RNA binders of therapeutic potential.
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Affiliation(s)
- Saddam Y Khatik
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Sarupa Roy
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
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2
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Copp W, Karimi A, Yang T, Guarné A, Luedtke NW. Fluorescent molecular rotors detect O6-methylguanine dynamics and repair in duplex DNA. Chem Commun (Camb) 2024; 60:1156-1159. [PMID: 38190113 DOI: 10.1039/d3cc04782b] [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: 01/09/2024]
Abstract
Alkylation at the O6 position of guanine is a common and highly mutagenic form of DNA damage. Direct repair of O6-alkylguanines by the "suicide" enzyme O6-methylguanine DNA methyltransferase (MGMT, AGT, AGAT) maintains genome stability and inhibits carcinogenesis. In this study, a fluorescent analogue of thymidine containing trans-stilbene (tsT) is quenched by O6-methylguanine residues in the opposite strand of DNA by molecular dynamics that propagate through the duplex with as much as ∼9 Å of separation. Increased fluorescence of tsT or the cytosine analogue tsC resulting from MGMT-mediated DNA repair were distinguishable from non-covalent DNA-protein binding following protease digest. To our knowledge, this is the first study utilizing molecular rotor base analogues to detect DNA damage and repair activities in duplex DNA.
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Affiliation(s)
- William Copp
- Department of Chemistry, McGill University, H3A-0B8 Montreal, Canada
- Centre de Recherche en Biologie Structural, McGill University, H3G 0B1 Montreal, Canada
| | - Ashkan Karimi
- Department of Chemistry, McGill University, H3A-0B8 Montreal, Canada
- Centre de Recherche en Biologie Structural, McGill University, H3G 0B1 Montreal, Canada
| | - Tianxiao Yang
- Centre de Recherche en Biologie Structural, McGill University, H3G 0B1 Montreal, Canada
- Department of Biochemistry, McGill University, H3G 1Y6 Montreal, Canada
| | - Alba Guarné
- Centre de Recherche en Biologie Structural, McGill University, H3G 0B1 Montreal, Canada
- Department of Biochemistry, McGill University, H3G 1Y6 Montreal, Canada
| | - Nathan W Luedtke
- Department of Chemistry, McGill University, H3A-0B8 Montreal, Canada
- Centre de Recherche en Biologie Structural, McGill University, H3G 0B1 Montreal, Canada
- Department of Pharmacology and Therapeutics, McGill University, H3A-1A3 Montreal, Canada
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3
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Wei J, Song Z, Cui J, Gong Y, Tang Q, Zhang K, Song X, Liao X. Entropy-driven assisted T7 RNA polymerase amplification-activated CRISPR/Cas13a activity for SARS-CoV-2 detection in human pharyngeal swabs and environment by an electrochemiluminescence biosensor. JOURNAL OF HAZARDOUS MATERIALS 2023; 452:131268. [PMID: 36965355 DOI: 10.1016/j.jhazmat.2023.131268] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 05/03/2023]
Abstract
In this study, we introduce an electrochemiluminescence (ECL) sensing platform based on the "Entropy-driven triggered T7 amplification-CRISPR/Cas13a system" (EDT-Cas). This platform combines a programmable entropy-driven cycling strategy, T7 RNA polymerase, and the CRISPR/Cas13a system to amplify the determination of the SARS-CoV-2 RdRp gene. The Ti3C2Tx-compliant ECL signaling molecule offers unique benefits when used with the ECL sensing platform to increase the assay sensitivity and the electrode surface modifiability. To obtain the T7 promoter, the SARS-CoV-2 RdRp gene may first initiate an entropy-driven cyclic amplification response. Then, after recognizing the T7 promoter sequence on the newly created dsDNA, T7 RNA polymerase starts transcription, resulting in the production of many single-stranded RNAs (ssRNAs), which in turn trigger the action of CRISPR/Cas13a. Finally, Cas13a/crRNA identifies the transcribed ssRNA. When it cleaves the ssRNA, many DNA reporter probes carrying -U-U- are cleaved on the electrode surface, increasing the ECL signal and allowing for the rapid and highly sensitive detection of SARS-CoV-2. With a detection limit of 7.39 aM, our method enables us to locate the SARS-CoV-2 RdRp gene in clinical samples. The detection method also demonstrates excellent repeatability and stability. The SARS-CoV-2 RdRp gene was discovered using the "Entropy-driven triggered T7 amplification-CRISPR/Cas13a system" (EDT-Cas). The developed ECL test had excellent recoveries in pharyngeal swabs and environmental samples. It is anticipated to offer an early clinical diagnosis of SARS-CoV-2 and further control the spread of the pandemic.
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Affiliation(s)
- Jihua Wei
- Guangxi Key Laboratory of Basic and Translational Research of Bone and Joint Degenerative Disease, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi 533000, China
| | - Zichun Song
- West Guangxi Key Laboratory for Prevention and Treatment of High-incidence Diseases, Youjiang Medical University for Nationalities, Baise, Guangxi 533000, China
| | - Jiuying Cui
- West Guangxi Key Laboratory for Prevention and Treatment of High-incidence Diseases, Youjiang Medical University for Nationalities, Baise, Guangxi 533000, China
| | - Yuanxun Gong
- Guangxi Key Laboratory of Basic and Translational Research of Bone and Joint Degenerative Disease, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi 533000, China
| | - Qianli Tang
- Guangxi Key Laboratory of Basic and Translational Research of Bone and Joint Degenerative Disease, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi 533000, China
| | - Kai Zhang
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China.
| | - Xinlei Song
- Maternity & Child Care Center of Dezhou, Dezhou 253000, China.
| | - Xianjiu Liao
- West Guangxi Key Laboratory for Prevention and Treatment of High-incidence Diseases, Youjiang Medical University for Nationalities, Baise, Guangxi 533000, China.
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4
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Wang D, Shalamberidze A, Arguello AE, Purse BW, Kleiner RE. Live-Cell RNA Imaging with Metabolically Incorporated Fluorescent Nucleosides. J Am Chem Soc 2022; 144:14647-14656. [PMID: 35930766 PMCID: PMC9940818 DOI: 10.1021/jacs.2c04142] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fluorescence imaging is a powerful method for probing macromolecular dynamics in biological systems; however, approaches for cellular RNA imaging are limited to the investigation of individual RNA constructs or bulk RNA labeling methods compatible primarily with fixed samples. Here, we develop a platform for fluorescence imaging of bulk RNA dynamics in living cells. We show that fluorescent bicyclic and tricyclic cytidine analogues can be metabolically incorporated into cellular RNA by overexpression of uridine-cytidine kinase 2. In particular, metabolic feeding with the tricyclic cytidine-derived nucleoside tC combined with confocal imaging enables the investigation of RNA synthesis, degradation, and trafficking at single-cell resolution. We apply our imaging modality to study RNA metabolism and localization during the oxidative stress response and find that bulk RNA turnover is greatly accelerated upon NaAsO2 treatment. Furthermore, we identify cytoplasmic RNA granules containing RNA transcripts generated during oxidative stress that are distinct from canonical stress granules and P-bodies and co-localize with the RNA helicase DDX6. Taken together, our work provides a powerful approach for live-cell RNA imaging and reveals how cells reshape RNA transcriptome dynamics in response to oxidative stress.
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Affiliation(s)
- Danyang Wang
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Ana Shalamberidze
- Department of Chemistry and Biochemistry and the Viral Information Institute, San Diego State University, San Diego, CA 92182, USA
| | | | - Byron W. Purse
- Department of Chemistry and Biochemistry and the Viral Information Institute, San Diego State University, San Diego, CA 92182, USA
| | - Ralph E. Kleiner
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
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5
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Nilsson JR, Baladi T, Gallud A, Baždarević D, Lemurell M, Esbjörner EK, Wilhelmsson LM, Dahlén A. Fluorescent base analogues in gapmers enable stealth labeling of antisense oligonucleotide therapeutics. Sci Rep 2021; 11:11365. [PMID: 34059711 PMCID: PMC8166847 DOI: 10.1038/s41598-021-90629-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/13/2021] [Indexed: 01/28/2023] Open
Abstract
To expand the antisense oligonucleotide (ASO) fluorescence labeling toolbox beyond covalent conjugation of external dyes (e.g. ATTO-, Alexa Fluor-, or cyanine dyes), we herein explore fluorescent base analogues (FBAs) as a novel approach to endow fluorescent properties to ASOs. Both cytosine and adenine analogues (tC, tCO, 2CNqA, and pA) were incorporated into a 16mer ASO sequence with a 3-10-3 cEt-DNA-cEt (cEt = constrained ethyl) gapmer design. In addition to a comprehensive photophysical characterization, we assess the label-induced effects on the gapmers' RNA affinities, RNA-hybridized secondary structures, and knockdown efficiencies. Importantly, we find practically no perturbing effects for gapmers with single FBA incorporations in the biologically critical gap region and, except for pA, the FBAs do not affect the knockdown efficiencies. Incorporating two cytosine FBAs in the gap is equally well tolerated, while two adenine analogues give rise to slightly reduced knockdown efficiencies and what could be perturbed secondary structures. We furthermore show that the FBAs can be used to visualize gapmers inside live cells using fluorescence microscopy and flow cytometry, enabling comparative assessment of their uptake. This altogether shows that FBAs are functional ASO probes that provide a minimally perturbing in-sequence labeling option for this highly relevant drug modality.
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Affiliation(s)
- Jesper R Nilsson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Tom Baladi
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96, Gothenburg, Sweden.,Medicinal Chemistry, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.,Oligonucleotide Discovery, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Audrey Gallud
- Department of Biology and Biological Engineering, Chalmers University of Technology, 41296, Gothenburg, Sweden.,Advanced Drug Delivery, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - Dženita Baždarević
- Bioscience, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Malin Lemurell
- Medicinal Chemistry, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Elin K Esbjörner
- Department of Biology and Biological Engineering, Chalmers University of Technology, 41296, Gothenburg, Sweden
| | - L Marcus Wilhelmsson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Anders Dahlén
- Oligonucleotide Discovery, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
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6
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Baladi T, Nilsson JR, Gallud A, Celauro E, Gasse C, Levi-Acobas F, Sarac I, Hollenstein MR, Dahlén A, Esbjörner EK, Wilhelmsson LM. Stealth Fluorescence Labeling for Live Microscopy Imaging of mRNA Delivery. J Am Chem Soc 2021; 143:5413-5424. [PMID: 33797236 PMCID: PMC8154517 DOI: 10.1021/jacs.1c00014] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
![]()
Methods for tracking
RNA inside living cells without perturbing
their natural interactions and functions are critical within biology
and, in particular, to facilitate studies of therapeutic RNA delivery.
We present a stealth labeling approach that can efficiently, and with
high fidelity, generate RNA transcripts, through enzymatic incorporation
of the triphosphate of tCO, a fluorescent tricyclic cytosine
analogue. We demonstrate this by incorporation of tCO in
up to 100% of the natural cytosine positions of a 1.2 kb mRNA encoding
for the histone H2B fused to GFP (H2B:GFP). Spectroscopic characterization
of this mRNA shows that the incorporation rate of tCO is
similar to cytosine, which allows for efficient labeling and controlled
tuning of labeling ratios for different applications. Using live cell
confocal microscopy and flow cytometry, we show that the tCO-labeled mRNA is efficiently translated into H2B:GFP inside human
cells. Hence, we not only develop the use of fluorescent base analogue
labeling of nucleic acids in live-cell microscopy but also, importantly,
show that the resulting transcript is translated into the correct
protein. Moreover, the spectral properties of our transcripts and
their translation product allow for their straightforward, simultaneous
visualization in live cells. Finally, we find that chemically transfected
tCO-labeled RNA, unlike a state-of-the-art fluorescently
labeled RNA, gives rise to expression of a similar amount of protein
as its natural counterpart, hence representing a methodology for studying
natural, unperturbed processing of mRNA used in RNA therapeutics and
in vaccines, like the ones developed against SARS-CoV-2.
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Affiliation(s)
- Tom Baladi
- Department of Chemistry and Chemical Engineering, Chemistry and Biochemistry, Chalmers University of Technology, SE-41296 Gothenburg, Sweden.,Medicinal Chemistry, Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Jesper R Nilsson
- Department of Chemistry and Chemical Engineering, Chemistry and Biochemistry, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
| | - Audrey Gallud
- Department of Biology and Biological Engineering, Chemical Biology, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
| | - Emanuele Celauro
- Department of Biology and Biological Engineering, Chemical Biology, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
| | - Cécile Gasse
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91057 Evry, France
| | - Fabienne Levi-Acobas
- Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, Institut Pasteur, 28, Rue du Docteur Roux, 75724 Paris CEDEX 15, France
| | - Ivo Sarac
- Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, Institut Pasteur, 28, Rue du Docteur Roux, 75724 Paris CEDEX 15, France
| | - Marcel R Hollenstein
- Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, Institut Pasteur, 28, Rue du Docteur Roux, 75724 Paris CEDEX 15, France
| | - Anders Dahlén
- Medicinal Chemistry, Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Elin K Esbjörner
- Department of Biology and Biological Engineering, Chemical Biology, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
| | - L Marcus Wilhelmsson
- Department of Chemistry and Chemical Engineering, Chemistry and Biochemistry, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
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7
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Liu Q, Ke Y, Kan Y, Tang X, Li X, He Y, Wu L. Compatibility and Fidelity of Mirror-Image Thymidine in Transcription Events by T7 RNA Polymerase. MOLECULAR THERAPY. NUCLEIC ACIDS 2020; 21:604-613. [PMID: 32721880 PMCID: PMC7390857 DOI: 10.1016/j.omtn.2020.06.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/15/2020] [Accepted: 06/23/2020] [Indexed: 11/16/2022]
Abstract
Due to highly enzymatic d-stereoselectivity, l-nucleotides (l-2'-deoxynucleoside 5'-triphosphates [l-dNTPs]) are not natural targets of polymerases. In this study, we synthesized series of l-thymidine (l-T)-modified DNA strands and evaluated the processivity of nucleotide incorporation for transcription by T7 RNA polymerase (RNAP) with an l-T-containing template. When single l-T was introduced into the transcribed region, transcription proceeded to afford the full-length transcript with different efficiencies. However, introduction of l-T into the non-transcribed region did not exhibit a noticeable change in the transcription efficiency. Surprisingly, when two consecutive or internal l-Ts were introduced into the transcribed region, no transcripts were detected. Compared to natural template, significant lags in NTP incorporation into the template T+4/N and T+7/N (where the number corresponds to the site of l-T position, and + means downstream of the transcribed region) were detected by kinetic analysis. Furthermore, affinity of template T+4/N was almost the same with T/N, whereas affinity of T+7/N was apparently increased. Furthermore, no mismatch opposite to l-T in the template was detected in transcription reactions via gel fidelity analysis. These results demonstrate the effects of chiral l-T in DNA on the efficiency and fidelity of RNA transcription mediated by T7 RNAP, which provides important knowledge about how mirror-image thymidine perturbs the flow of genetic information during RNA transcription and development of diseases caused by gene mutation.
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Affiliation(s)
- Qingju Liu
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongqi Ke
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuhe Kan
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinjing Tang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Xiangjun Li
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Yujian He
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
| | - Li Wu
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
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8
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Turner MB, Purse BW. Fluorescent Tricyclic Cytidine Analogues as Substrates for Retroviral Reverse Transcriptases. Chempluschem 2020; 85:855-865. [PMID: 32378814 DOI: 10.1002/cplu.202000140] [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: 02/26/2020] [Revised: 04/21/2020] [Indexed: 11/05/2022]
Abstract
We report on the ability of the reverse transcriptases (RTs) from avian myeloblastosis virus (AMV), Moloney murine leukemia virus (M-MLV), and human immunodeficiency virus 1 (HIV-1) to generate labeled DNA using the fluorescent tricyclic cytidine analogues d(tC)TP and d(DEA tC)TP as substrates. Michaelis-Menten kinetics for the insertion of these analogues show Vmax /KM from 0.0-5 times that of natural dCTP across from G, depending on the polymerase and whether the template is RNA or DNA. The analogues are prone to misinsertion across from adenosine with both RNA and DNA templates. Elongation after analogue insertion is efficient with RNA templates, but the analogues cause stalling after insertion with DNA templates. A model reverse transcription assay using HIV-1-RT, including RNA-dependent DNA synthesis, degradation of the RNA template by the RT's RNase H activity, and synthesis of a second DNA strand to form fluorescently labeled dsDNA, shows that d(tC)TP and d(DEA tC)TP are compatible with a complete reverse transcription cycle in vitro.
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Affiliation(s)
- M Benjamin Turner
- Department of Chemistry and Biochemistry and the Viral Information Institute, San Diego State University, San Diego, CA, 92182, USA
| | - Byron W Purse
- Department of Chemistry and Biochemistry and the Viral Information Institute, San Diego State University, San Diego, CA, 92182, USA
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9
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Flamme M, McKenzie LK, Sarac I, Hollenstein M. Chemical methods for the modification of RNA. Methods 2019; 161:64-82. [PMID: 30905751 DOI: 10.1016/j.ymeth.2019.03.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 02/06/2023] Open
Abstract
RNA is often considered as being the vector for the transmission of genetic information from DNA to the protein synthesis machinery. However, besides translation RNA participates in a broad variety of fundamental biological roles such as gene expression and regulation, protein synthesis, and even catalysis of chemical reactions. This variety of function combined with intricate three-dimensional structures and the discovery of over 100 chemical modifications in natural RNAs require chemical methods for the modification of RNAs in order to investigate their mechanism, location, and exact biological roles. In addition, numerous RNA-based tools such as ribozymes, aptamers, or therapeutic oligonucleotides require the presence of additional chemical functionalities to strengthen the nucleosidic backbone against degradation or enhance the desired catalytic or binding properties. Herein, the two main methods for the chemical modification of RNA are presented: solid-phase synthesis using phosphoramidite precursors and the enzymatic polymerization of nucleoside triphosphates. The different synthetic and biochemical steps required for each method are carefully described and recent examples of practical applications based on these two methods are discussed.
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Affiliation(s)
- Marie Flamme
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France; Sorbonne Université, Collège doctoral, F-75005 Paris, France
| | - Luke K McKenzie
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Ivo Sarac
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Marcel Hollenstein
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France.
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10
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Milisavljevič N, Perlíková P, Pohl R, Hocek M. Enzymatic synthesis of base-modified RNA by T7 RNA polymerase. A systematic study and comparison of 5-substituted pyrimidine and 7-substituted 7-deazapurine nucleoside triphosphates as substrates. Org Biomol Chem 2019; 16:5800-5807. [PMID: 30063056 DOI: 10.1039/c8ob01498a] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We synthesized a small library of eighteen 5-substituted pyrimidine or 7-substituted 7-deazapurine nucleoside triphosphates bearing methyl, ethynyl, phenyl, benzofuryl or dibenzofuryl groups through cross-coupling reactions of nucleosides followed by triphosphorylation or through direct cross-coupling reactions of halogenated nucleoside triphosphates. We systematically studied the influence of the modification on the efficiency of T7 RNA polymerase catalyzed synthesis of modified RNA and found that modified ATP, UTP and CTP analogues bearing smaller modifications were good substrates and building blocks for the RNA synthesis even in difficult sequences incorporating multiple modified nucleotides. Bulky dibenzofuryl derivatives of ATP and GTP were not substrates for the RNA polymerase. In the case of modified GTP analogues, a modified procedure using a special promoter and GMP as initiator needed to be used to obtain efficient RNA synthesis. The T7 RNA polymerase synthesis of modified RNA can be very efficiently used for synthesis of modified RNA but the method has constraints in the sequence of the first three nucleotides of the transcript, which must contain a non-modified G in the +1 position.
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Affiliation(s)
- Nemanja Milisavljevič
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, CZ-16610, Prague 6, Czech Republic.
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11
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Sinclair WR, Arango D, Shrimp JH, Zengeya TT, Thomas JM, Montgomery DC, Fox SD, Andresson T, Oberdoerffer S, Meier JL. Profiling Cytidine Acetylation with Specific Affinity and Reactivity. ACS Chem Biol 2017; 12:2922-2926. [PMID: 29039931 DOI: 10.1021/acschembio.7b00734] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The human acetyltransferase NAT10 has recently been shown to catalyze formation of N4-acetylcytidine (ac4C), a minor nucleobase known to alter RNA structure and function. In order to better understand the role of RNA acetyltransferases in biology and disease, here we report the development and application of chemical methods to study ac4C. First, we demonstrate that ac4C can be conjugated to carrier proteins using optimized protocols. Next, we describe methods to access ac4C-containing RNAs, enabling the screening of anti-ac4C antibodies. Finally, we validate the specificity of an optimized ac4C affinity reagent in the context of cellular RNA by demonstrating its ability to accurately report on chemical deacetylation of ac4C. Overall, these studies provide a powerful new tool for studying ac4C in biological contexts, as well as new insights into the stability and half-life of this highly conserved RNA modification. More broadly, they demonstrate how chemical reactivity may be exploited to aid the development and validation of nucleobase-targeting affinity reagents designed to target the emerging epitranscriptome.
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Affiliation(s)
- Wilson R. Sinclair
- Chemical
Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, United States
| | - Daniel Arango
- Laboratory
of Receptor Biology and Gene Expression, Center for Cancer Research,
National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20817, United States
| | - Jonathan H. Shrimp
- Chemical
Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, United States
| | - Thomas T. Zengeya
- Chemical
Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, United States
| | - Justin M. Thomas
- Chemical
Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, United States
| | - David C. Montgomery
- Chemical
Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, United States
| | - Stephen D. Fox
- Protein
Characterization Laboratory, Cancer Research Technology Program, Frederick
National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, Maryland 21702, United States
| | - Thorkell Andresson
- Protein
Characterization Laboratory, Cancer Research Technology Program, Frederick
National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, Maryland 21702, United States
| | - Shalini Oberdoerffer
- Laboratory
of Receptor Biology and Gene Expression, Center for Cancer Research,
National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20817, United States
| | - Jordan L. Meier
- Chemical
Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, United States
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12
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Mei H, Shi C, Jimenez RM, Wang Y, Kardouh M, Chaput JC. Synthesis and polymerase activity of a fluorescent cytidine TNA triphosphate analogue. Nucleic Acids Res 2017; 45:5629-5638. [PMID: 28472363 PMCID: PMC5449585 DOI: 10.1093/nar/gkx368] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 04/21/2017] [Indexed: 02/04/2023] Open
Abstract
Threose nucleic acid (TNA) is an artificial genetic polymer capable of undergoing Darwinian evolution to produce aptamers with affinity to specific targets. This property, coupled with a backbone structure that is refractory to nuclease digestion, makes TNA an attractive biopolymer system for diagnostic and therapeutic applications. Expanding the chemical diversity of TNA beyond the natural bases would enable the development of functional TNA molecules with enhanced physiochemical properties. Here, we describe the synthesis and polymerase activity of a fluorescent cytidine TNA triphosphate analogue (1,3-diaza-2-oxo-phenothiazine, tCfTP) that maintains Watson-Crick base pairing with guanine. Polymerase-mediated primer-extension assays reveal that tCfTP is efficiently added to the growing end of a TNA primer. Detailed kinetic assays indicate that tCfTP and tCTP have comparable rates for the first nucleotide incorporation step (kobs1). However, addition of the second nucleotide (kobs2) is 700-fold faster for tCfTP than tCTP due the increased effects of base stacking. Last, we found that TNA replication using tCfTP in place of tCTP exhibits 98.4% overall fidelity for the combined process of TNA transcription and reverse transcription. Together, these results expand the chemical diversity of enzymatically generated TNA molecules to include a hydrophobic base analogue with strong fluorescent properties that is compatible with in vitro selection.
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Affiliation(s)
- Hui Mei
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
| | - Changhua Shi
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
| | - Randi M Jimenez
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
| | - Yajun Wang
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
| | - Miramar Kardouh
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
| | - John C Chaput
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
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13
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Füchtbauer AF, Preus S, Börjesson K, McPhee SA, Lilley DMJ, Wilhelmsson LM. Fluorescent RNA cytosine analogue - an internal probe for detailed structure and dynamics investigations. Sci Rep 2017; 7:2393. [PMID: 28539582 PMCID: PMC5443824 DOI: 10.1038/s41598-017-02453-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 04/10/2017] [Indexed: 12/22/2022] Open
Abstract
The bright fluorescent cytosine analogue tCO stands out among fluorescent bases due to its virtually unquenched fluorescence emission in duplex DNA. However, like most reported base analogues, it has not been thoroughly characterized in RNA. We here report on the first synthesis and RNA-incorporation of tCO, and characterize its base-mimicking and fluorescence properties in RNA. As in DNA, we find a high quantum yield inside RNA duplexes (<ΦF> = 0.22) that is virtually unaffected by the neighbouring bases (ΦF = 0.20-0.25), resulting in an average brightness of 1900 M-1 cm-1. The average fluorescence lifetime in RNA duplexes is 4.3 ns and generally two lifetimes are required to fit the exponential decays. Fluorescence properties in ssRNA are defined by a small increase in average quantum yield (<ΦF > = 0.24) compared to dsRNA, with a broader distribution (ΦF = 0.17-0.34) and slightly shorter average lifetimes. Using circular dichroism, we find that the tCO-modified RNA duplexes form regular A-form helices and in UV-melting experiments the stability of the duplexes is only slightly higher than that of the corresponding natural RNA (<ΔT m> = + 2.3 °C). These properties make tCO a highly interesting fluorescent RNA base analogue for detailed FRET-based structural measurements, as a bright internal label in microscopy, and for fluorescence anisotropy measurements of RNA dynamics.
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Affiliation(s)
- Anders Foller Füchtbauer
- Chemistry and Chemical Engineering/Chemistry and Biochemistry, Chalmers University of Technology, Gothenburg, SE-41296, Sweden
| | - Søren Preus
- Department of Chemistry, University of Copenhagen, Copenhagen, DK-2100, Denmark
| | - Karl Börjesson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, SE-41296, Sweden
| | - Scott A McPhee
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - David M J Lilley
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - L Marcus Wilhelmsson
- Chemistry and Chemical Engineering/Chemistry and Biochemistry, Chalmers University of Technology, Gothenburg, SE-41296, Sweden.
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14
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Burns DD, Teppang KL, Lee RW, Lokensgard ME, Purse BW. Fluorescence Turn-On Sensing of DNA Duplex Formation by a Tricyclic Cytidine Analogue. J Am Chem Soc 2017; 139:1372-1375. [PMID: 28080035 DOI: 10.1021/jacs.6b10410] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Most fluorescent nucleoside analogues are quenched when base stacked and some maintain their brightness, but there has been little progress toward developing nucleoside analogues that markedly increase their fluorescence upon duplex formation. Here, we report on the design and synthesis of a new tricyclic cytidine analogue, 8-diethylamino-tC (8-DEA-tC), that responds to DNA duplex formation with up to a 20-fold increase in fluorescent quantum yield as compared with the free nucleoside, depending on neighboring bases. This turn-on response to duplex formation is the greatest of any reported nucleoside analogue that can participate in Watson-Crick base pairing. Measurements of the quantum yield of 8-DEA-tC mispaired with adenosine and, separately, opposite an abasic site show that there is almost no fluorescence increase without the formation of correct Watson-Crick hydrogen bonds. Kinetic isotope effects from the use of deuterated buffer show that the duplex protects 8-DEA-tC against quenching by excited state proton transfer. These results, supported by DFT calculations, suggest a rationale for the observed photophysical properties that is dependent on duplex integrity and the electronic structure of the analogue.
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Affiliation(s)
- Dillon D Burns
- Department of Chemistry and Biochemistry, San Diego State University , San Diego, California 92182, United States
| | - Kristine L Teppang
- Department of Chemistry and Biochemistry, San Diego State University , San Diego, California 92182, United States
| | - Raymond W Lee
- Department of Chemistry and Biochemistry, San Diego State University , San Diego, California 92182, United States
| | - Melissa E Lokensgard
- Department of Chemistry and Biochemistry, San Diego State University , San Diego, California 92182, United States
| | - Byron W Purse
- Department of Chemistry and Biochemistry, San Diego State University , San Diego, California 92182, United States
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15
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Bosáková A, Perlíková P, Tichý M, Pohl R, Hocek M. 6-Aryl-4-amino-pyrimido[4,5-b]indole 2'-deoxyribonucleoside triphosphates (benzo-fused 7-deaza-dATP analogues): Synthesis, fluorescent properties, enzymatic incorporation into DNA and DNA-protein binding study. Bioorg Med Chem 2016; 24:4528-4535. [PMID: 27498304 DOI: 10.1016/j.bmc.2016.07.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/22/2016] [Accepted: 07/25/2016] [Indexed: 01/03/2023]
Abstract
Four 6-substituted 4-amino-pyrimido[4,5-b]indole 2'-deoxyribonucleoside triphosphates (dA(BX)TPs) were prepared by glycosylation of 4,6-dichloropyrimidoindole followed by ammonolysis, cross-coupling and triphosphorylation. They were found to be moderate to good substrates for DNA polymerases in primer extension. They also exerted fluorescence with emission maxima 335-378nm. When incorporated to oligonucleotide probes, they did not show significant mismatch discrimination but the 6-benzofuryl 4-amino-pyrimido[4,5-b]indole nucleotide displayed a useful sensitivity to protein binding in experiment with SSB protein.
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Affiliation(s)
- Andrea Bosáková
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences & IOCB Research Center, Flemingovo nam. 2, CZ-16610 Prague 6, Czech Republic
| | - Pavla Perlíková
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences & IOCB Research Center, Flemingovo nam. 2, CZ-16610 Prague 6, Czech Republic
| | - Michal Tichý
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences & IOCB Research Center, Flemingovo nam. 2, CZ-16610 Prague 6, Czech Republic
| | - Radek Pohl
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences & IOCB Research Center, Flemingovo nam. 2, CZ-16610 Prague 6, Czech Republic
| | - Michal Hocek
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences & IOCB Research Center, Flemingovo nam. 2, CZ-16610 Prague 6, Czech Republic; Department of Organic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, CZ-12843 Prague 2, Czech Republic.
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16
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Zheng Y, Beal PA. Synthesis and evaluation of an alkyne-modified ATP analog for enzymatic incorporation into RNA. Bioorg Med Chem Lett 2016; 26:1799-802. [PMID: 26927424 PMCID: PMC4785081 DOI: 10.1016/j.bmcl.2016.02.038] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/13/2016] [Accepted: 02/15/2016] [Indexed: 11/17/2022]
Abstract
Alkyne-modified nucleoside analogs are useful for nucleic acid localization as well as functional and structural studies because of their ability to participate in copper-catalyzed azide/alkyne cycloaddition (CuAAC) reactions. Here we describe the synthesis of the triphosphate of 7-ethynyl-8-aza-7-deazaadenosine (7-EAATP) and the enzymatic incorporation of 7-EAA into RNA. The free nucleoside of 7-EAA is taken up by HeLa cells and incorporated into cellular RNA by endogenous RNA polymerases. In addition, 7-EAATP is a substrate for both T7 RNA polymerase and poly (A) polymerase from Escherichia coli in vitro, albeit at lower efficiencies than with ATP. This work adds to the toolbox of nucleoside analogs useful for RNA labeling.
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Affiliation(s)
- Yuxuan Zheng
- University of California, Davis, Department of Chemistry, One Shields Ave, Davis 95616, CA, USA
| | - Peter A Beal
- University of California, Davis, Department of Chemistry, One Shields Ave, Davis 95616, CA, USA.
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17
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McCoy LS, Shin D, Tor Y. Isomorphic emissive GTP surrogate facilitates initiation and elongation of in vitro transcription reactions. J Am Chem Soc 2014; 136:15176-84. [PMID: 25255464 PMCID: PMC4227834 DOI: 10.1021/ja5039227] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The fastidious behavior of T7 RNA
polymerase limits the incorporation
of synthetic nucleosides into RNA transcripts, particularly at or
near the promoter. The practically exclusive use of GTP for transcription
initiation further compounds this challenge, and reactions with GTP
analogs, where the heterocyclic nucleus has been altered, have not,
to our knowledge, been demonstrated. The enzymatic incorporation of thGTP, a newly synthesized isomorphic fluorescent nucleotide
with a thieno[3,4-d]pyrimidine core, is explored.
The modified nucleotide can initiate and maintain transcription reactions,
leading to the formation of fully modified and highly emissive RNA
transcripts with thG replacing all guanosine residues.
Short and long modified transcripts are synthesized in comparable
yields to their natural counterparts. To assess proper folding and
function, transcripts were used to assemble a hammerhead ribozyme
with all permutations of natural and modified enzyme and substrate
strands. The thG modified substrate was effectively cleaved
by the natural RNA enzyme, demonstrating the isomorphic features of
the nucleoside and its ability to replace G residues while retaining
proper folding. In contrast, the thG modified enzyme showed
little cleavage ability, suggesting the modifications likely disrupted
the catalytic center, illustrating the significance of the Hoogsteen
face in mediating appropriate contacts. Importantly, the ribozyme
cleavage reaction of the emissive fluorescent transcripts could be
followed in real time by fluorescence spectroscopy. Beyond their utility
as fluorescent probes in biophysical and discovery assays, the results
reported point to the potential utility of such isomorphic nucleosides
in probing specific mechanistic questions in RNA catalysis and RNA
structural analysis.
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Affiliation(s)
- Lisa S McCoy
- Department of Chemistry and Biochemistry, University of California , San Diego, La Jolla, California 92093-0358, United States
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18
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Tanpure AA, Srivatsan SG. Synthesis, photophysical properties and incorporation of a highly emissive and environment-sensitive uridine analogue based on the Lucifer chromophore. Chembiochem 2014; 15:1309-16. [PMID: 24861713 DOI: 10.1002/cbic.201402052] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Indexed: 11/10/2022]
Abstract
The majority of fluorescent nucleoside analogues used in nucleic acid studies have excitation maxima in the UV region and show very low fluorescence within oligonucleotides (ONs); hence, they cannot be utilised with certain fluorescence methods and for cell-based analysis. Here, we describe the synthesis, photophysical properties and incorporation of a highly emissive and environment-sensitive uridine analogue, derived by attaching a Lucifer chromophore (1,8-naphthalimide core) at the 5-position of uracil. The emissive nucleoside displays excitation and emission maxima in the visible region and exhibits high quantum yield. Importantly, when incorporated into ON duplexes it retains appreciable fluorescence efficiency and is sensitive to the neighbouring base environment. Notably, the nucleoside signals the presence of purine repeats in ON duplexes with an enhancement in fluorescence intensity, a property rarely displayed by other nucleoside analogues.
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Affiliation(s)
- Arun A Tanpure
- Department of Chemistry, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008 (India)
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19
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Rodgers BJ, Elsharif NA, Vashisht N, Mingus MM, Mulvahill MA, Stengel G, Kuchta RD, Purse BW. Functionalized tricyclic cytosine analogues provide nucleoside fluorophores with improved photophysical properties and a range of solvent sensitivities. Chemistry 2013; 20:2010-5. [PMID: 24311229 DOI: 10.1002/chem.201303410] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Indexed: 12/11/2022]
Abstract
Tricyclic cytosines (tC and tC(O) frameworks) have emerged as a unique class of fluorescent nucleobase analogues that minimally perturb the structure of B-form DNA and that are not quenched in duplex nucleic acids. Systematic derivatization of these frameworks is a likely approach to improve on and diversify photophysical properties, but has not so far been examined. Synthetic methods were refined to improve on tolerance for electron-donating and electron-withdrawing groups, resulting in a series of eight new, fluorescent cytidine analogues. Photophysical studies show that substitution of the framework results in a pattern of effects largely consistent across tC and tC(O) and provides nucleoside fluorophores that are brighter than either parent. Moreover, a range of solvent sensitivities is observed, offering promise that this family of probes can be extended to new applications that require reporting on the local environment.
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Affiliation(s)
- Brittney J Rodgers
- Department of Chemistry and Biochemistry, University of Denver, 2199 S. University Blvd., Denver, CO 80208 (USA)
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20
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Tanpure AA, Pawar MG, Srivatsan SG. Fluorescent Nucleoside Analogs: Probes for Investigating Nucleic Acid Structure and Function. Isr J Chem 2013. [DOI: 10.1002/ijch.201300010] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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21
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Tanpure AA, Srivatsan SG. Synthesis and photophysical characterisation of a fluorescent nucleoside analogue that signals the presence of an abasic site in RNA. Chembiochem 2012; 13:2392-9. [PMID: 23070860 DOI: 10.1002/cbic.201200408] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Indexed: 11/07/2022]
Abstract
The synthesis and site-specific incorporation of an environment-sensitive fluorescent nucleoside analogue (2), based on a 5-(benzofuran-2-yl)pyrimidine core, into DNA oligonucleotides (ONs), and its photophysical properties within these ONs are described. Interestingly and unlike 2-aminopurine (a widely used nucleoside analogue probe), when incorporated into an ON and hybridised with a complementary ON, the emissive nucleoside 2 displays significantly higher emission intensity than the free nucleoside. Furthermore, photophysical characterisation shows that the fluorescence properties of the nucleoside analogue within ONs are significantly influenced by flanking bases, especially by guanosine. By utilising the responsiveness of the nucleoside to changes in base environment, a DNA ON reporter labelled with the emissive nucleoside 2 was constructed; this signalled the presence of an abasic site in a model depurinated sarcin/ricin RNA motif of a eukaryotic 28S rRNA.
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Affiliation(s)
- Arun A Tanpure
- Department of Chemistry, Indian Institute of Science Education and Research, 900, NCL Innovation Park, Dr. Homi Bhabha Road, Pune 411008, India
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22
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Rao H, Tanpure AA, Sawant AA, Srivatsan SG. Enzymatic incorporation of an azide-modified UTP analog into oligoribonucleotides for post-transcriptional chemical functionalization. Nat Protoc 2012; 7:1097-112. [PMID: 22576108 DOI: 10.1038/nprot.2012.046] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This protocol describes the detailed experimental procedure for the synthesis of an azide-modified uridine triphosphate analog and its effective incorporation into an oligoribonucleotide by in vitro transcription reactions. Furthermore, procedures for labeling azide-modified oligoribonucleotides post-transcriptionally with biophysical probes by copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) and Staudinger reactions are also provided. This post-transcriptional chemical modification protocol is simple and modular, and it affords labeled oligonucleotides in reasonable amounts for biophysical assays. The procedure for enzymatic incorporation of the monophosphate of azide-modified UTP into an oligoribonucleotide transcript takes ∼2 d, and subsequent post-transcriptional chemical functionalization of the transcript takes about 2 d.
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Affiliation(s)
- Harita Rao
- Department of Chemistry, Indian Institute of Science Education and Research, Pune, India
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23
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Abstract
The past several years have seen numerous reports of new chemical modifications for use in RNA. In addition, in that time period, we have seen the discovery of several previously unknown naturally occurring modifications that impart novel properties on the parent RNAs. In this review, we describe recent discoveries in these areas with a focus on RNA modifications that introduce spectroscopic tags, reactive handles, or new recognition properties.
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Affiliation(s)
- Kelly Phelps
- Department
of Chemistry, University of California, Davis, California 95616, United States
| | - Alexi Morris
- Department
of Chemistry, University of California, Davis, California 95616, United States
| | - Peter A. Beal
- Department
of Chemistry, University of California, Davis, California 95616, United States
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24
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Tanpure AA, Srivatsan SG. A microenvironment-sensitive fluorescent pyrimidine ribonucleoside analogue: synthesis, enzymatic incorporation, and fluorescence detection of a DNA abasic site. Chemistry 2011; 17:12820-7. [PMID: 21956450 DOI: 10.1002/chem.201101194] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 07/18/2011] [Indexed: 11/10/2022]
Abstract
Base-modified fluorescent ribonucleoside-analogue probes are valuable tools in monitoring RNA structure and function because they closely resemble the structure of natural nucleobases. Especially, 2-aminopurine, a highly environment-sensitive adenosine analogue, is the most extensively utilized fluorescent nucleoside analogue. However, only a few isosteric pyrimidine ribonucleoside analogues that are suitable for probing the structure and recognition properties of RNA molecules are available. Herein, we describe the synthesis and photophysical characterization of a small series of base-modified pyrimidine ribonucleoside analogues derived from tagging indole, N-methylindole, and benzofuran onto the 5-position of uracil. One of the analogues, based on a 5-(benzofuran-2-yl)pyrimidine core, shows emission in the visible region with a reasonable quantum yield and, importantly, displays excellent solvatochromism. The corresponding triphosphate substrate is effectively incorporated into oligoribonucleotides by T7 RNA polymerase to produce fluorescent oligoribonucleotide constructs. Steady-state and time-resolved spectroscopic studies with fluorescent oligoribonucleotide constructs demonstrate that the fluorescent ribonucleoside photophysically responds to subtle changes in its environment brought about by the interaction of the chromophore with neighboring bases. In particular, the emissive ribonucleoside, if incorporated into an oligoribonucleotide, positively reports the presence of a DNA abasic site with an appreciable enhancement in fluorescence intensity. The straightforward synthesis, amicability to enzymatic incorporation, and sensitivity to changes in the microenvironment highlight the potential of the benzofuran-conjugated pyrimidine ribonucleoside as an efficient fluorescent probe to investigate nucleic acid structure, dynamics, and recognition events.
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Affiliation(s)
- Arun A Tanpure
- Department of Chemistry, Indian Institute of Science Education and Research, Pashan, Pune, India
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25
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Sato K, Sasaki A, Matsuda A. Highly fluorescent 5-(5,6-dimethoxybenzothiazol-2-yl)-2'-deoxyuridine 5'-triphosphate as an efficient substrate for DNA polymerases. Chembiochem 2011; 12:2341-6. [PMID: 21887841 DOI: 10.1002/cbic.201100452] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Indexed: 11/08/2022]
Abstract
We herein describe the synthesis of fluorescent 5-(5,6-dimethoxybenzothiazol-2-yl)-2'-deoxyuridine 5'-triphosphate (d(bt)UTP) and primer extension reactions using d(bt)UTP. We also carried out primer extension reactions using the (bt)U template. B family DNA polymerases, such as KOD, Deep Vent (exo-), and 9°N(m) DNA polymerases, were effective for elongation with d(bt)UTP. Deep Vent (exo-) and KOD DNA polymerases have excellent fidelity for incorporating d(bt)UTP only at the site opposite the adenine template and only dATP when using the (bt)U template. Therefore, d(bt)UTP is an excellent fluorescent nucleotide that can be incorporated into DNA by DNA polymerases.
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Affiliation(s)
- Kousuke Sato
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Sapporo 060-0812, Japan
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26
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Kimoto M, Cox RS, Hirao I. Unnatural base pair systems for sensing and diagnostic applications. Expert Rev Mol Diagn 2011; 11:321-31. [PMID: 21463241 DOI: 10.1586/erm.11.5] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Expansion of the genetic alphabet by an unnatural base pair system provides a platform for the site-specific, enzymatic incorporation of extra, functional components into nucleic acids. Recently, several unnatural base pairs that exhibit high fidelity and efficiency in PCR have been developed. Functional groups of interest, such as fluorescent dyes, can be linked to the unnatural bases, and the modified base substrates are site-specifically incorporated into nucleic acids by polymerases. Furthermore, unique unnatural base pairs between fluorophore and quencher base analogs have been developed for imaging PCR amplification and as molecular beacons. Here, we describe the recent progress in the development of unnatural base pairs that function in PCR amplification and their applications as sensing and diagnostic tools.
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Affiliation(s)
- Michiko Kimoto
- RIKEN Systems and Structural Biology Center (SSBC), Yokohama, Japan
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27
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Discrimination against the Cytosine Analog tC by Escherichia coli DNA Polymerase IV DinB. J Mol Biol 2011; 409:89-100. [DOI: 10.1016/j.jmb.2011.03.069] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 03/27/2011] [Accepted: 03/30/2011] [Indexed: 01/30/2023]
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28
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Shukla GC, Haque F, Tor Y, Wilhelmsson LM, Toulmé JJ, Isambert H, Guo P, Rossi JJ, Tenenbaum SA, Shapiro BA. A boost for the emerging field of RNA nanotechnology. ACS NANO 2011; 5:3405-18. [PMID: 21604810 PMCID: PMC3102291 DOI: 10.1021/nn200989r] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
This Nano Focus article highlights recent advances in RNA nanotechnology as presented at the First International Conference of RNA Nanotechnology and Therapeutics, which took place in Cleveland, OH, USA (October 23-25, 2010) ( http://www.eng.uc.edu/nanomedicine/RNA2010/ ), chaired by Peixuan Guo and co-chaired by David Rueda and Scott Tenenbaum. The conference was the first of its kind to bring together more than 30 invited speakers in the frontier of RNA nanotechnology from France, Sweden, South Korea, China, and throughout the United States to discuss RNA nanotechnology and its applications. It provided a platform for researchers from academia, government, and the pharmaceutical industry to share existing knowledge, vision, technology, and challenges in the field and promoted collaborations among researchers interested in advancing this emerging scientific discipline. The meeting covered a range of topics, including biophysical and single-molecule approaches for characterization of RNA nanostructures; structure studies on RNA nanoparticles by chemical or biochemical approaches, computation, prediction, and modeling of RNA nanoparticle structures; methods for the assembly of RNA nanoparticles; chemistry for RNA synthesis, conjugation, and labeling; and application of RNA nanoparticles in therapeutics. A special invited talk on the well-established principles of DNA nanotechnology was arranged to provide models for RNA nanotechnology. An Administrator from National Institutes of Health (NIH) National Cancer Institute (NCI) Alliance for Nanotechnology in Cancer discussed the current nanocancer research directions and future funding opportunities at NCI. As indicated by the feedback received from the invited speakers and the meeting participants, this meeting was extremely successful, exciting, and informative, covering many groundbreaking findings, pioneering ideas, and novel discoveries.
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Affiliation(s)
- Girish C. Shukla
- Center for Gene Regulation in Health and Disease, Department of Biological Sciences, Cleveland State University, Cleveland, Ohio 44115, United States
| | - Farzin Haque
- Nanobiomedical Center, College of Engineering and Applied Science, and College of Medicine, University of Cincinnati, Cincinnati, Ohio 45267, United States
| | - Yitzhak Tor
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - L. Marcus Wilhelmsson
- Department of Chemical and Biological Engineering/Physical Chemistry, Chalmers University of Technology, Kemivägen 10, SE-412 96 Göteborg, Sweden
| | - Jean-Jacques Toulmé
- Université Bordeaux Segalen, INSERM U869, Bâtiment 3A 1er étage, 33076 Bordeaux Cedex, France
| | - Hervé Isambert
- Institut Curie, Research Division, CNRS UMR 168, 11 rue P. & M. Curie, 75005 Paris, France
| | - Peixuan Guo
- Nanobiomedical Center, College of Engineering and Applied Science, and College of Medicine, University of Cincinnati, Cincinnati, Ohio 45267, United States
| | - John J. Rossi
- Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, Duarte, California 91010, United States
| | - Scott A. Tenenbaum
- College of Nanoscale Science & Engineering, University at Albany-SUNY, Albany, New York 12203, United States
| | - Bruce A. Shapiro
- Center for Cancer Research Nanobiology Program, National Cancer Institute at Frederick, Frederick, Maryland 21702, United States
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29
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Stengel G, Purse BW, Kuchta RD. Effect of transition metal ions on the fluorescence and Taq-catalyzed polymerase chain reaction of tricyclic cytidine analogs. Anal Biochem 2011; 416:53-60. [PMID: 21600183 DOI: 10.1016/j.ab.2011.04.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 04/14/2011] [Accepted: 04/21/2011] [Indexed: 12/11/2022]
Abstract
The cytosine analogs 1,3-diaza-2-oxophenothiazine (tC) and 1,3-diaza-2-oxophenoxazine (tCo) stand out among fluorescent bases due to their unquenched fluorescence emission in double-stranded DNA. Recently, we reported a method for the generation of densely tCo-labeled DNA by polymerase chain reaction (PCR) that relied on the use of the extremely thermostable Deep Vent polymerase. We have now developed a protocol that employs the more commonly used Taq polymerase. Supplementing the PCR with Mn(2+) or Co(2+) ions dramatically increased the amount of tCo triphosphate (dtCoTP) incorporated and, thus, enhanced the brightness of the PCR products. The resulting PCR products could be easily detected in gels based on their intrinsic fluorescence. The Mn(2+) ions modulate the PCR by improving the bypass of template tCo and the overall catalytic efficiency. In contrast to the lower fidelity during tCo bypass, Mn(2+) improved the ability of Taq polymerase to distinguish between dtCoTP and dTTP when copying a template dA. Interestingly, Mn(2+) ions hardly affect the fluorescence emission of tC(o), whereas the coordination of Co(2+) ions with the phosphate groups of DNA and nucleotides statically quenches tC(o) fluorescence with small reciprocal Stern-Vollmer constants of 10-300μM.
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Affiliation(s)
- Gudrun Stengel
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
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30
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Hernández AR, Kool ET. The components of xRNA: synthesis and fluorescence of a full genetic set of size-expanded ribonucleosides. Org Lett 2011; 13:676-9. [PMID: 21214222 PMCID: PMC3039074 DOI: 10.1021/ol102915f] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The synthesis and properties of a full set of four benzo-expanded ribonucleosides (xRNA), analogous to A, G, C, and U RNA monomers, are described. The nucleosides are efficient fluorophores with emission maxima of 369-411 nm. The compounds are expected to be useful as RNA pathway probes and as components of an unnatural ribopolymer.
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Affiliation(s)
| | - Eric T. Kool
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
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31
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Shu Y, Cinier M, Shu D, Guo P. Assembly of multifunctional phi29 pRNA nanoparticles for specific delivery of siRNA and other therapeutics to targeted cells. Methods 2011; 54:204-14. [PMID: 21320601 DOI: 10.1016/j.ymeth.2011.01.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 01/06/2011] [Accepted: 01/20/2011] [Indexed: 01/31/2023] Open
Abstract
Recent advances in RNA nanotechnology have led to the emergence of a new field and brought vitality to the area of therapeutics [P. Guo, The emerging field of RNA nanotechnology, Nat. Nanotechnol., 2010]. Due to the complementary nature of the four nucleotides and its special catalytic activity, RNA can be manipulated with simplicity characteristic of DNA, while possessing versatile structure and diverse function similar to proteins. Loops and tertiary architecture serve as mounting dovetails or wedges to eliminate external linking dowels. Unique features in transcription, termination, self-assembly, self-processing, and acid-resistance enable in vivo production of nanoparticles harboring aptamer, siRNA, ribozyme, riboswitch, or other regulators for therapy, detection, regulation, and intracellular computation. The unique property of noncanonical base-pairing and stacking enables RNA to fold into well-defined structures for constructing nanoparticles with special functionalities. Bacteriophage phi29 DNA packaging motor is geared by a ring consisting of six packaging RNA (pRNA) molecules. pRNA is able to form a multimeric complex via the interaction of two reengineered interlocking loops. This unique feature makes it an ideal polyvalent vehicle for nanomachine fabrication, pathogen detection, and delivery of siRNA or other therapeutics. This review describes methods in using pRNA as a building block for the construction of RNA dimers, trimers, and hexamers as nanoparticles in medical applications. Methods for industrial-scale production of large and stable RNA nanoparticles will be introduced. The unique favorable PK (pharmacokinetics) profile with a half life (T(1/2)) of 5-10h comparing to 0.25 of conventional 2'-F siRNA, and advantageous in vivo features such as non-toxicity, non-induction of interferons or non-stimulating of cytokine response in animals will also be reviewed.
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Affiliation(s)
- Yi Shu
- Nanobiomedical Center, University of Cincinnati, Cincinnati, OH 45267, USA
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32
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Dierckx A, Dinér P, El-Sagheer AH, Kumar JD, Brown T, Grøtli M, Wilhelmsson LM. Characterization of photophysical and base-mimicking properties of a novel fluorescent adenine analogue in DNA. Nucleic Acids Res 2011; 39:4513-24. [PMID: 21278417 PMCID: PMC3105426 DOI: 10.1093/nar/gkr010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
To increase the diversity of fluorescent base analogues with improved properties, we here present the straightforward click-chemistry-based synthesis of a novel fluorescent adenine-analogue triazole adenine (AT) and its photophysical characterization inside DNA. AT shows promising properties compared to the widely used adenine analogue 2-aminopurine. Quantum yields reach >20% and >5% in single- and double-stranded DNA, respectively, and show dependence on neighbouring bases. Moreover, AT shows only a minor destabilization of DNA duplexes, comparable to 2-aminopurine, and circular dichroism investigations suggest that AT only causes minimal structural perturbations to normal B-DNA. Furthermore, we find that AT shows favourable base-pairing properties with thymine and more surprisingly also with normal adenine. In conclusion, AT shows strong potential as a new fluorescent adenine analogue for monitoring changes within its microenvironment in DNA.
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Affiliation(s)
- Anke Dierckx
- Department of Chemical and Biological Engineering/Physical Chemistry, Chalmers University of Technology, University of Gothenburg, S-41296 Gothenburg, Sweden
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Pawar MG, Srivatsan SG. Synthesis, photophysical characterization, and enzymatic incorporation of a microenvironment-sensitive fluorescent uridine analog. Org Lett 2011; 13:1114-7. [PMID: 21275418 DOI: 10.1021/ol103147t] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The synthesis of a microenvironment-sensitive base-modified fluorescent ribonucleoside analog based on a 5-(benzo[b]thiophen-2-yl)pyrimidine core, enzymatic incorporation of its corresponding triphosphate into RNA oligonucleotides, and photophysical characterization of fluorescently modified oligoribonucleotides are described.
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Affiliation(s)
- Maroti G Pawar
- Indian Institute of Science Education and Research, Pashan, Pune, India
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Abstract
Like DNA, RNA can be designed and manipulated to produce a variety of different nanostructures. Moreover, RNA has a flexible structure and possesses catalytic functions that are similar to proteins. Although RNA nanotechnology resembles DNA nanotechnology in many ways, the base-pairing rules for constructing nanoparticles are different. The large variety of loops and motifs found in RNA allows it to fold into numerous complicated structures, and this diversity provides a platform for identifying viable building blocks for various applications. The thermal stability of RNA also allows the production of multivalent nanostructures with defined stoichiometry. Here we review techniques for constructing RNA nanoparticles from different building blocks, we describe the distinct attributes of RNA inside the body, and discuss potential applications of RNA nanostructures in medicine. We also offer some perspectives on the yield and cost of RNA production.
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Affiliation(s)
- Peixuan Guo
- Nanobiomedical Center, College of Engineering and College of Medicine, University of Cincinnati, Cincinnati, Ohio 45221, USA.
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35
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Site-specific fluorescent probing of RNA molecules by unnatural base-pair transcription for local structural conformation analysis. Nat Protoc 2010; 5:1312-23. [DOI: 10.1038/nprot.2010.77] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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36
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Abstract
The use of fluorescent nucleic acid base analogues is becoming increasingly important in the fields of biology, biochemistry and biophysical chemistry as well as in the field of DNA nanotechnology. The advantage of being able to incorporate a fluorescent probe molecule close to the site of examination in the nucleic acid-containing system of interest with merely a minimal perturbation to the natural structure makes fluorescent base analogues highly attractive. In recent years, there has been a growing interest in developing novel candidates in this group of fluorophores for utilization in various investigations. This review describes the different classes of fluorophores that can be used for studying nucleic acid-containing systems, with an emphasis on choosing the right kind of probe for the system under investigation. It describes the characteristics of the large group of base analogues that has an emission that is sensitive to the surrounding microenvironment and gives examples of investigations in which this group of molecules has been used so far. Furthermore, the characterization and use of fluorescent base analogues that are virtually insensitive to changes in their microenvironment are described in detail. This group of base analogues can be used in several fluorescence investigations of nucleic acids, especially in fluorescence anisotropy and fluorescence resonance energy transfer (FRET) measurements. Finally, the development and characterization of the first nucleic base analogue FRET pair, tC(O)-tC(nitro), and its possible future uses are discussed.
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