1
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Rusling DA. Triplex-forming properties and enzymatic incorporation of a base-modified nucleotide capable of duplex DNA recognition at neutral pH. Nucleic Acids Res 2021; 49:7256-7266. [PMID: 34233006 PMCID: PMC8287925 DOI: 10.1093/nar/gkab572] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/31/2021] [Accepted: 07/06/2021] [Indexed: 11/14/2022] Open
Abstract
The sequence-specific recognition of duplex DNA by unmodified parallel triplex-forming oligonucleotides is restricted to low pH conditions due to a necessity for cytosine protonation in the third strand. This has severely restricted their use as gene-targeting agents, as well as for the detection and/or functionalisation of synthetic or genomic DNA. Here I report that the nucleobase 6-amino-5-nitropyridin-2-one (Z) finally overcomes this constraint by acting as an uncharged mimic of protonated cytosine. Synthetic TFOs containing the nucleobase enabled stable and selective triplex formation at oligopurine-oligopyrimidine sequences containing multiple isolated or contiguous GC base pairs at neutral pH and above. Moreover, I demonstrate a universal strategy for the enzymatic assembly of Z-containing TFOs using its commercially available deoxyribonucleotide triphosphate. These findings seek to improve not only the recognition properties of TFOs but also the cost and/or expertise associated with their chemical syntheses.
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Affiliation(s)
- David A Rusling
- School of Biological Sciences, University of Southampton, Southampton, Hampshire SO17 1BJ, UK
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2
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Ryan CA, Brodyagin N, Lok J, Rozners E. The 2-Aminopyridine Nucleobase Improves Triple-Helical Recognition of RNA and DNA When Used Instead of Pseudoisocytosine in Peptide Nucleic Acids. Biochemistry 2021; 60:1919-1925. [PMID: 34097400 DOI: 10.1021/acs.biochem.1c00275] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Pseudoisocytosine (J), a neutral analogue of protonated cytosine, is currently the gold standard modified nucleobase in peptide nucleic acids (PNAs) for the formation of J·G-C triplets that are stable at physiological pH. This study shows that triple-helical recognition of RNA and DNA is significantly improved by using 2-aminopyridine (M) instead of J. The positively charged M forms 3-fold stronger M+·G-C triplets than J with uncompromised sequence selectivity. Replacement of six Js with Ms in a PNA 9-mer increased its binding affinity by ∼2 orders of magnitude. M-modified PNAs prefer binding double-stranded RNA over DNA and disfavor off-target binding to single-stranded nucleic acids. Taken together, the results show that M is a promising modified nucleobase that significantly improves triplex-forming PNAs and may provide breakthrough developments for therapeutic and biotechnology applications.
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Affiliation(s)
- Christopher A Ryan
- Department of Chemistry, Binghamton University, The State University of New York, Binghamton, New York 13902, United States
| | - Nikita Brodyagin
- Department of Chemistry, Binghamton University, The State University of New York, Binghamton, New York 13902, United States
| | - Justin Lok
- Department of Chemistry, Binghamton University, The State University of New York, Binghamton, New York 13902, United States
| | - Eriks Rozners
- Department of Chemistry, Binghamton University, The State University of New York, Binghamton, New York 13902, United States
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3
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Pabon-Martinez YV, Xu Y, Villa A, Lundin KE, Geny S, Nguyen CH, Pedersen EB, Jørgensen PT, Wengel J, Nilsson L, Smith CIE, Zain R. LNA effects on DNA binding and conformation: from single strand to duplex and triplex structures. Sci Rep 2017; 7:11043. [PMID: 28887512 PMCID: PMC5591256 DOI: 10.1038/s41598-017-09147-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 07/20/2017] [Indexed: 12/19/2022] Open
Abstract
The anti-gene strategy is based on sequence-specific recognition of double-strand DNA by triplex forming (TFOs) or DNA strand invading oligonucleotides to modulate gene expression. To be efficient, the oligonucleotides (ONs) should target DNA selectively, with high affinity. Here we combined hybridization analysis and electrophoretic mobility shift assay with molecular dynamics (MD) simulations to better understand the underlying structural features of modified ONs in stabilizing duplex- and triplex structures. Particularly, we investigated the role played by the position and number of locked nucleic acid (LNA) substitutions in the ON when targeting a c-MYC or FXN (Frataxin) sequence. We found that LNA-containing single strand TFOs are conformationally pre-organized for major groove binding. Reduced content of LNA at consecutive positions at the 3'-end of a TFO destabilizes the triplex structure, whereas the presence of Twisted Intercalating Nucleic Acid (TINA) at the 3'-end of the TFO increases the rate and extent of triplex formation. A triplex-specific intercalating benzoquinoquinoxaline (BQQ) compound highly stabilizes LNA-containing triplex structures. Moreover, LNA-substitution in the duplex pyrimidine strand alters the double helix structure, affecting x-displacement, slide and twist favoring triplex formation through enhanced TFO major groove accommodation. Collectively, these findings should facilitate the design of potent anti-gene ONs.
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Affiliation(s)
- Y Vladimir Pabon-Martinez
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86, Huddinge, Stockholm, Sweden
| | - You Xu
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83, Huddinge, Sweden
| | - Alessandra Villa
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83, Huddinge, Sweden
| | - Karin E Lundin
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86, Huddinge, Stockholm, Sweden
| | - Sylvain Geny
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86, Huddinge, Stockholm, Sweden
| | - Chi-Hung Nguyen
- Institut Curie, PSL Research University, UMR 9187-U 1196, CNRS-Institut Curie, INSERM, Centre Universitaire, Orsay, France
| | - Erik B Pedersen
- Department of Physics, Chemistry and Pharmacy, Nucleic Acid Center, University of Southern Denmark, DK-5230, Odense M, Denmark
| | - Per T Jørgensen
- Department of Physics, Chemistry and Pharmacy, Nucleic Acid Center, University of Southern Denmark, DK-5230, Odense M, Denmark
| | - Jesper Wengel
- Department of Physics, Chemistry and Pharmacy, Nucleic Acid Center, University of Southern Denmark, DK-5230, Odense M, Denmark
| | - Lennart Nilsson
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83, Huddinge, Sweden
| | - C I Edvard Smith
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86, Huddinge, Stockholm, Sweden
| | - Rula Zain
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86, Huddinge, Stockholm, Sweden.
- Department of Clinical Genetics, Centre for Rare Diseases, Karolinska University Hospital, SE-171 76, Stockholm, Sweden.
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4
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Minero GAS, Fock J, McCaskill JS, Hansen MF. Optomagnetic detection of DNA triplex nanoswitches. Analyst 2017; 142:582-585. [DOI: 10.1039/c6an02419j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Triplex DNA formation is studied using rapid low-cost and dose-dependent optomagnetic method with an assay time of max 10 min and limit of detection of 100 pM.
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Affiliation(s)
- Gabriel Antonio S. Minero
- Department of Micro- and Nanotechnology
- Technical University of Denmark
- DTU Nanotech
- DK-2800 Kongens Lyngby
- Denmark
| | - Jeppe Fock
- Department of Micro- and Nanotechnology
- Technical University of Denmark
- DTU Nanotech
- DK-2800 Kongens Lyngby
- Denmark
| | - John S. McCaskill
- Ruhr-Universitaet Bochum
- Microsystems Chemistry and BioIT (BioMIP)
- NC3
- 44801 Bochum
- Germany
| | - Mikkel F. Hansen
- Department of Micro- and Nanotechnology
- Technical University of Denmark
- DTU Nanotech
- DK-2800 Kongens Lyngby
- Denmark
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5
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RNA-dependent DNA endonuclease Cas9 of the CRISPR system: Holy Grail of genome editing? Trends Microbiol 2013; 21:562-7. [DOI: 10.1016/j.tim.2013.09.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 09/02/2013] [Accepted: 09/04/2013] [Indexed: 12/23/2022]
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6
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Cardew AS, Brown T, Fox KR. Secondary binding sites for heavily modified triplex forming oligonucleotides. Nucleic Acids Res 2011; 40:3753-62. [PMID: 22180535 PMCID: PMC3333850 DOI: 10.1093/nar/gkr1119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In order to enhance DNA triple helix stability synthetic oligonucleotides have been developed that bear amino groups on the sugar or base. One of the most effective of these is bis-amino-U (B), which possesses 5-propargylamino and 2′-aminoethoxy modifications. Inclusion of this modified nucleotide not only greatly enhances triplex stability, but also increases the affinity for related sequences. We have used a restriction enzyme protection, selection and amplification assay (REPSA) to isolate sequences that are bound by the heavily modified 9-mer triplex-forming oligonucleotide B6CBT. The isolated sequences contain An tracts (n = 6), suggesting that the 5′-end of this TFO was responsible for successful triplex formation. DNase I footprinting with these sequences confirmed triple helix formation at these secondary targets and demonstrated no interaction with similar oligonucleotides containing T or 5-propargylamino-dU.
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Affiliation(s)
- Antonia S Cardew
- Centre for Biological Sciences, Life Sciences Building, University of Southampton, Southampton SO17 1BJ, UK
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7
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Abstract
Triple-helical nucleic acids are formed by binding an oligonucleotide within the major groove of duplex DNA. These complexes offer the possibility of designing oligonucleotides which bind to duplex DNA with considerable sequence specificity. However, triple-helix formation with natural nucleotides is limited by (i) the requirement for low pH, (ii) the requirement for homopurine target sequences, and (iii) their relatively low affinity. We have prepared modified oligonucleotides to overcome these limitations, including the addition of positive charges to the sugar and/or base, the inclusion of cytosine analogues, the development of nucleosides for recognition of pyrimidine interruptions and the attachment of one or more cross-linking groups. By these means we are able to generate triplexes which have high affinities at physiological pH at sequences that contain pyrimidine interruptions.
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8
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Kolevzon N, Yavin E. Site-Specific DNA Photocleavage and Photomodulation by Oligonucleotide Conjugates. Oligonucleotides 2010; 20:263-75. [DOI: 10.1089/oli.2010.0247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Netanel Kolevzon
- The School of Pharmacy, The Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Eylon Yavin
- The School of Pharmacy, The Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
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9
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Rusling DA, Rachwal PA, Brown T, Fox KR. The stability of triplex DNA is affected by the stability of the underlying duplex. Biophys Chem 2009; 145:105-10. [PMID: 19819611 DOI: 10.1016/j.bpc.2009.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 09/16/2009] [Accepted: 09/16/2009] [Indexed: 11/16/2022]
Abstract
We have studied the formation of DNA triple helices in different sequence contexts and show that, for the most stable triplexes, their apparent stability is affected by the stability of the underlying duplex. For a 14-mer parallel triplex-forming oligonucleotide (generating C(+).GC and T.AT triplets) at pH 5.0 the T(m) is more than 10 degrees C lower with an intermolecular 14-mer duplex target, than it is with an intramolecular duplex, or one which is flanked by 6 GC base pairs at either end. A similar effect is seen with triplex-forming oligonucleotides that contain stabilising analogues, for which the T(m) is higher for an intramolecular than an intermolecular duplex target. These results suggest that the use of simple intermolecular duplex targets may underestimate the triplex stabilisation that is produced by some nucleotide analogues.
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Affiliation(s)
- David A Rusling
- School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
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10
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Bergstrom DE. Unnatural nucleosides with unusual base pairing properties. ACTA ACUST UNITED AC 2009; Chapter 1:1.4.1-1.4.32. [PMID: 19488968 DOI: 10.1002/0471142700.nc0104s37] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Synthetic modified nucleosides designed to pair in unusual ways with natural nucleobases have many potential applications in biology and biotechnology. This overview lays the foundation for future protocol units on synthesis and application of unnatural bases, with particular emphasis on unnatural base analogs that mimic natural bases in size, shape, and biochemical processing. Topics covered include base pairs with alternative H-bonding schemes, dimensionally expanded base pairs, hydrophobic base pairs, metal-ligated bases, degenerate bases, universal nucleosides, and triplex constituents.
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11
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Rusling DA, Peng G, Srinivasan N, Fox KR, Brown T. DNA triplex formation with 5-dimethylaminopropargyl deoxyuridine. Nucleic Acids Res 2009; 37:1288-96. [PMID: 19139069 PMCID: PMC2651792 DOI: 10.1093/nar/gkn1060] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We have prepared triplex-forming oligonucleotides containing the nucleotide analogue 5-dimethylaminopropargyl deoxyuridine (DMAPdU) in place of thymidine and examined their ability to form intermolecular triple helices by thermal melting and DNase I footprinting studies. The results were compared with those for oligonucleotides containing 5-aminopropargyl-dU (APdU), 5-guanidinopropargyl-dU (GPdU) and 5-propynyl dU (PdU). We find that DMAPdU enhances triplex stability relative to T, though slightly less than the other analogues that bear positive charges (T << PdU < DMAPdU < APdU < GPdU). For oligonucleotides that contain multiple substitutions with DMAPdU dispersed residues are more effective than clustered combinations. DMAPdU will be especially useful as a nucleotide analogue as, unlike APdU and GPdU, the base does not require protection during oligonucleotide synthesis and it can therefore be used with other derivatives that require mild deprotection conditions.
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Affiliation(s)
- David A Rusling
- School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
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12
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Li H, Miller PS, Seidman MM. Selectivity and affinity of DNA triplex forming oligonucleotides containing the nucleoside analogues 2'-O-methyl-5-(3-amino-1-propynyl)uridine and 2'-O-methyl-5-propynyluridine. Org Biomol Chem 2008; 6:4212-7. [PMID: 18972052 DOI: 10.1039/b810709b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Triplex forming oligonucleotides (TFOs) containing the nucleoside analogues 2'-O-methyl-5-propynyluridine (1) and 2'-O-methyl-5-(3-amino-1-propynyl)uridine (2) were synthesized. The affinity and selectivity of triplex formation by these TFOs were studied by gel shift analysis, T(m) value measurement, and association rate assays. The results show that the introduction of 1 and 2 into TFOs can improve the stability of the triplexes under physiological conditions. Optimized distribution of 1 or 2 in the TFOs combined with a cluster of contiguous nucleosides with 2'-aminoethoxy sugars resulted in formation of triplexes with further enhanced stability and improved selectivity.
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Affiliation(s)
- Hong Li
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
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13
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Duca M, Vekhoff P, Oussedik K, Halby L, Arimondo PB. The triple helix: 50 years later, the outcome. Nucleic Acids Res 2008; 36:5123-38. [PMID: 18676453 PMCID: PMC2532714 DOI: 10.1093/nar/gkn493] [Citation(s) in RCA: 265] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Triplex-forming oligonucleotides constitute an interesting DNA sequence-specific tool that can be used to target cleaving or cross-linking agents, transcription factors or nucleases to a chosen site on the DNA. They are not only used as biotechnological tools but also to induce modifications on DNA with the aim to control gene expression, such as by site-directed mutagenesis or DNA recombination. Here, we report the state of art of the triplex-based anti-gene strategy 50 years after the discovery of such a structure, and we show the importance of the actual applications and the main challenges that we still have ahead of us.
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Affiliation(s)
- Maria Duca
- LCMBA CNRS UMR6001, University of Nice-Sophia Antipolis, Parc Valrose, 06108 NICE Cedex 2, France
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14
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Tumpane J, Kumar R, Lundberg EP, Sandin P, Gale N, Nandhakumar IS, Albinsson B, Lincoln P, Wilhelmsson LM, Brown T, Nordén B. Triplex addressability as a basis for functional DNA nanostructures. NANO LETTERS 2007; 7:3832-3839. [PMID: 17983251 DOI: 10.1021/nl072512i] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Here, we present the formation of a fully addressable DNA nanostructure that shows the potential to be exploited as, for example, an information storage device based on pH-driven triplex strand formation or nanoscale circuits based on electron transfer. The nanostructure is composed of two adjacent hexagonal unit cells (analogous to naphthalene) in which each of the eleven edges has a unique double-stranded DNA sequence, constructed using novel three-way oligonucleotides. This allows each ten base-pair side, just 3.4 nm in length, to be assigned a specific address according to its sequence. Such constructs are therefore an ideal precursor to a nonrepetitive two-dimensional grid on which the "addresses" are located at a precise and known position. Triplex recognition of these addresses could function as a simple yet efficient means of information storage and retrieval. Future applications that may be envisaged include nanoscale circuits as well as subnanometer precision in nanoparticle templating. Characterization of these precursor nanostructures and their reversible targeting by triplex strand formation is shown here using gel electrophoresis, atomic force microscopy, and fluorescence resonance energy transfer (FRET) measurements. The durability of the system to repeated cycling of pH switching is also confirmed by the FRET studies.
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Affiliation(s)
- John Tumpane
- Department of Chemical and Biological Engineering/Physical Chemistry, Chalmers University of Technology, SE-41296, Gothenburg, Sweden
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15
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Rusling DA, Broughton-Head VJ, Tuck A, Khairallah H, Osborne SD, Brown T, Fox KR. Kinetic studies on the formation of DNA triplexes containing the nucleoside analogue 2'-O-(2-aminoethyl)-5-(3-amino-1-propynyl)uridine. Org Biomol Chem 2007; 6:122-9. [PMID: 18075656 DOI: 10.1039/b713088k] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We have examined the kinetics of triple helix formation of oligonucleotides that contain the nucleotide analogue 2'-O-(2-aminoethyl)-5-(3-amino-1-propynyl)uridine (bis-amino-U, BAU), which forms very stable base triplets with AT. Triplex stability is determined by both the number and location of the modifications. BAU-containing oligonucleotides generate triplexes with extremely slow kinetics, as evidenced by 14 degrees C hysteresis between annealing and melting profiles even when heated at a rate as slow as 0.2 degrees C min(-1). The association kinetics were measured by analysis of the hysteresis profiles, temperature-jump relaxation and DNase I footprinting. We find that the slow kinetics are largely due to the decreased rate of dissociation; BAU modification has little effect on the association reaction. The sequence selectivity is also due to the slower dissociation of BAU from AT than other base pairs.
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Affiliation(s)
- David A Rusling
- School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton, SO16 7PX, UK.
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16
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Rusling DA, Brown T, Fox KR. DNA triple-helix formation at target sites containing duplex mismatches. Biophys Chem 2006; 123:134-40. [PMID: 16735088 DOI: 10.1016/j.bpc.2006.04.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Revised: 04/28/2006] [Accepted: 04/29/2006] [Indexed: 11/29/2022]
Abstract
We have studied the formation of DNA triple helices at target sites that contain mismatches in the duplex target. Fluorescence melting studies were used to examine a series of parallel triple helices that contain all 64 N.XZ triplet combinations at the centre (where N, X and Z are each of the four natural DNA bases in turn). Similar experiments were also performed with N=bis-amino-U (BAU) (for stable recognition of AT base pairs) and N=S (for recognition of TA inversions). We find that the introduction of a duplex mismatch destabilises the C+.GZ, T.AZ and G.TZ triplets. A similar effect is seen with BAU.AZ triplets. In contrast, other base combinations, based on non-standard triplets such as C.AZ, T.TZ, G.CZ and A.CZ are stabilised by the presence of a duplex mismatch. In each case S binds to sites containing duplex mismatches better than the corresponding Watson-Crick base pairs.
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Affiliation(s)
- David A Rusling
- School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
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