1
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Tao S, Run Y, Monchaud D, Zhang W. i-Motif DNA: identification, formation, and cellular functions. Trends Genet 2024:S0168-9525(24)00133-1. [PMID: 38902139 DOI: 10.1016/j.tig.2024.05.011] [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: 04/24/2024] [Revised: 05/29/2024] [Accepted: 05/29/2024] [Indexed: 06/22/2024]
Abstract
An i-motif (iM) is a four-stranded (quadruplex) DNA structure that folds from cytosine (C)-rich sequences. iMs can fold under many different conditions in vitro, which paves the way for their formation in living cells. iMs are thought to play key roles in various DNA transactions, notably in the regulation of genome stability, gene transcription, mRNA translation, DNA replication, telomere and centromere functions, and human diseases. We summarize the different techniques used to assess the folding of iMs in vitro and provide an overview of the internal and external factors that affect their formation and stability in vivo. We describe the possible biological relevance of iMs and propose directions towards their use as target in biology.
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Affiliation(s)
- Shentong Tao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production (CIC-MCP), Nanjing Agricultural University, 1 Weigang, Nanjing, Jiangsu 210095, China
| | - Yonghang Run
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production (CIC-MCP), Nanjing Agricultural University, 1 Weigang, Nanjing, Jiangsu 210095, China
| | - David Monchaud
- Institut de Chimie Moleculaire de l'Université de Bourgogne (ICMUB), Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6302, Université Bourgogne Franche Comté (UBFC), Dijon, France
| | - Wenli Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production (CIC-MCP), Nanjing Agricultural University, 1 Weigang, Nanjing, Jiangsu 210095, China.
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2
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Feng Y, Ma X, Yang Y, Tao S, Ahmed A, Gong Z, Cheng X, Zhang W. The roles of DNA methylation on pH dependent i-motif (iM) formation in rice. Nucleic Acids Res 2024; 52:1243-1257. [PMID: 38180820 PMCID: PMC10853798 DOI: 10.1093/nar/gkad1245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 12/14/2023] [Accepted: 12/19/2023] [Indexed: 01/07/2024] Open
Abstract
I-motifs (iMs) are four-stranded non-B DNA structures containing C-rich DNA sequences. The formation of iMs is sensitive to pH conditions and DNA methylation, although the extent of which is still unknown in both humans and plants. To investigate this, we here conducted iMab antibody-based immunoprecipitation and sequencing (iM-IP-seq) along with bisulfite sequencing using CK (original genomic DNA without methylation-related treatments) and hypermethylated or demethylated DNA at both pH 5.5 and 7.0 in rice, establishing a link between pH, DNA methylation and iM formation on a genome-wide scale. We found that iMs folded at pH 7.0 displayed higher methylation levels than those formed at pH 5.5. DNA demethylation and hypermethylation differently influenced iM formation at pH 7.0 and 5.5. Importantly, CG hypo-DMRs (differentially methylated regions) and CHH (H = A, C and T) hyper-DMRs alone or coordinated with CG/CHG hyper-DMRs may play determinant roles in the regulation of pH dependent iM formation. Thus, our study shows that the nature of DNA sequences alone or combined with their methylation status plays critical roles in determining pH-dependent formation of iMs. It therefore deepens the understanding of the pH and methylation dependent modulation of iM formation, which has important biological implications and practical applications.
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Affiliation(s)
- Yilong Feng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, CIC-MCP, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, China
| | - Xing Ma
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, CIC-MCP, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, China
| | - Ying Yang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, CIC-MCP, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, China
| | - Shentong Tao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, CIC-MCP, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, China
| | - Asgar Ahmed
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, CIC-MCP, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, China
- Bangladesh Wheat and Maize Research Institute (BWMRI), Nashipur, Dinajpur 5200, Bangladesh
| | - Zhiyun Gong
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College of Yangzhou University, Yangzhou 225009, China
| | - Xuejiao Cheng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, CIC-MCP, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, China
| | - Wenli Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, CIC-MCP, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, China
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3
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Sun Y, Ji Y, Wang D, Wang J, Liu D. Stabilization of an intermolecular i-motif by lipid modification of cytosine-oligodeoxynucleotides. Org Biomol Chem 2019; 16:4857-4863. [PMID: 29926887 DOI: 10.1039/c8ob00920a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This paper describes the stabilization of an intermolecular i-motif by lipophilic modification on the 3'-terminus of oligonucleotides. The hydrophobic aliphatic chain connected at the 3'-terminus of a trinucleotide (dC)3 promoted the formation of an i-motif and significantly enhanced the quadruplex's stability. The impact of lipophilic modification on i-motif's thermal stability was studied by UV-thermal denaturation melting experiments and isothermal titration calorimetry. We found that alkyl chains containing more than 14 carbon atoms could elevate the i-motif structure's stability in a wide range of pH and concentrations.
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Affiliation(s)
- Yawei Sun
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum (Huadong), Qingdao, 258000, China.
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4
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Tsvetkov VB, Zatsepin TS, Belyaev ES, Kostyukevich YI, Shpakovski GV, Podgorsky VV, Pozmogova GE, Varizhuk AM, Aralov AV. i-Clamp phenoxazine for the fine tuning of DNA i-motif stability. Nucleic Acids Res 2018; 46:2751-2764. [PMID: 29474573 PMCID: PMC5888743 DOI: 10.1093/nar/gky121] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/01/2018] [Accepted: 02/13/2018] [Indexed: 12/13/2022] Open
Abstract
Non-canonical DNA structures are widely used for regulation of gene expression, in DNA nanotechnology and for the development of new DNA-based sensors. I-motifs (iMs) are two intercalated parallel duplexes that are held together by hemiprotonated C-C base pairs. Previously, iMs were used as an accurate sensor for intracellular pH measurements. However, iM stability is moderate, which in turn limits its in vivo applications. Here, we report the rational design of a new substituted phenoxazine 2'-deoxynucleotide (i-clamp) for iM stabilization. This residue contains a C8-aminopropyl tether that interacts with the phosphate group within the neighboring chain without compromising base pairing. We studied the influence of i-clamp on pH-dependent stability for intra- and intermolecular iM structures and found the optimal positions for modification. Two i-clamps on opposite strands provide thermal stabilization up to 10-11°C at a pH of 5.8. Thus, we developed a new modification that shows significant iM-stabilizing effect both at strongly and mildly acidic pH and increases iM transition pH values. i-Clamp can be used for tuning iM-based pH probes or assembling extra stable iM structures for various applications.
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Affiliation(s)
- Vladimir B Tsvetkov
- Biophysics Department, Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia
- Department of Molecular Virology, FSBI Research Institute of Influenza, Ministry of Health of Russian Federation, prof. Popov str. 15/17, Saint-Petersburg, 197376, Russia
- Polyelectrolytes and Biomedical Polymers Laboratory, A.V. Topchiev Institute of Petrochemical Synthesis, RAS, Leninsky prospect str. 29, Moscow 119991, Russia
| | - Timofei S Zatsepin
- Center for Translational Biomedicine, Skolkovo Institute of Science and Technology, 3 Nobel street, Skolkovo, Moscow 143026, Russia
- Chemistry Department, Lomonosov Moscow State University, Leninskie gory str. 1–3, Moscow 119992, Russia
| | - Evgeny S Belyaev
- Frumkin Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Science, Leninsky prospect str. 31, Moscow 119071 Russia
| | - Yury I Kostyukevich
- Center for Translational Biomedicine, Skolkovo Institute of Science and Technology, 3 Nobel street, Skolkovo, Moscow 143026, Russia
| | - George V Shpakovski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str. 16/10, Moscow 117997, Russia
| | - Victor V Podgorsky
- Biophysics Department, Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia
| | - Galina E Pozmogova
- Biophysics Department, Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia
| | - Anna M Varizhuk
- Biophysics Department, Research and Clinical Center for Physical Chemical Medicine, Malaya Pirogovskaya str. 1a, Moscow 119435, Russia
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, Moscow 119991, Russia
| | - Andrey V Aralov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str. 16/10, Moscow 117997, Russia
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5
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Liu G, Li Z, Zhu J, Liu Y, Zhou Y, He J. Studies on the thymine–mercury–thymine base pairing in parallel and anti-parallel DNA duplexes. NEW J CHEM 2015. [DOI: 10.1039/c5nj01859e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Parallel and anti-parallel T–Hg–T base pairs have different thermal stabilities and conformational influences on DNA duplex structures.
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Affiliation(s)
- Gaofeng Liu
- College of Life Sciences
- Guizhou University
- Guiyang 550025
- China
| | - Zhiwen Li
- College of Life Sciences
- Guizhou University
- Guiyang 550025
- China
| | - Junfei Zhu
- College of Life Sciences
- Guizhou University
- Guiyang 550025
- China
| | - Yang Liu
- School of Pharmacological Sciences
- Guangxi Medical University
- Nanning 530021
- China
| | - Ying Zhou
- College of Life Sciences
- Guizhou University
- Guiyang 550025
- China
| | - Junlin He
- Beijing Institute of Pharmacology and Toxicology
- Beijing 100850
- China
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6
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Gros C, Fleury L, Nahoum V, Faux C, Valente S, Labella D, Cantagrel F, Rilova E, Bouhlel MA, David-Cordonnier MH, Dufau I, Ausseil F, Mai A, Mourey L, Lacroix L, Arimondo PB. New insights on the mechanism of quinoline-based DNA Methyltransferase inhibitors. J Biol Chem 2014; 290:6293-302. [PMID: 25525263 PMCID: PMC4358266 DOI: 10.1074/jbc.m114.594671] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Among the epigenetic marks, DNA methylation is one of the most studied. It is highly deregulated in numerous diseases, including cancer. Indeed, it has been shown that hypermethylation of tumor suppressor genes promoters is a common feature of cancer cells. Because DNA methylation is reversible, the DNA methyltransferases (DNMTs), responsible for this epigenetic mark, are considered promising therapeutic targets. Several molecules have been identified as DNMT inhibitors and, among the non-nucleoside inhibitors, 4-aminoquinoline-based inhibitors, such as SGI-1027 and its analogs, showed potent inhibitory activity. Here we characterized the in vitro mechanism of action of SGI-1027 and two analogs. Enzymatic competition studies with the DNA substrate and the methyl donor cofactor, S-adenosyl-l-methionine (AdoMet), displayed AdoMet non-competitive and DNA competitive behavior. In addition, deviations from the Michaelis-Menten model in DNA competition experiments suggested an interaction with DNA. Thus their ability to interact with DNA was established; although SGI-1027 was a weak DNA ligand, analog 5, the most potent inhibitor, strongly interacted with DNA. Finally, as 5 interacted with DNMT only when the DNA duplex was present, we hypothesize that this class of chemical compounds inhibit DNMTs by interacting with the DNA substrate.
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Affiliation(s)
- Christina Gros
- From the Unité de Service et de Recherche CNRS-Pierre Fabre 3388, ETaC, CRDPF, 31100 Toulouse, France
| | - Laurence Fleury
- From the Unité de Service et de Recherche CNRS-Pierre Fabre 3388, ETaC, CRDPF, 31100 Toulouse, France
| | - Virginie Nahoum
- Institut de Pharmacologie et de Biologie Structurale (IPBS) CNRS, Toulouse, 31077, France, Université de Toulouse, UPS, IPBS, Toulouse, 31077, France
| | - Céline Faux
- From the Unité de Service et de Recherche CNRS-Pierre Fabre 3388, ETaC, CRDPF, 31100 Toulouse, France
| | - Sergio Valente
- Sapienza University of Rome, Department of Chemistry and Technology of Drug, Sapienza University of Rome, I-00185 Roma, Italy
| | - Donatella Labella
- Sapienza University of Rome, Department of Chemistry and Technology of Drug, Sapienza University of Rome, I-00185 Roma, Italy
| | - Frédéric Cantagrel
- From the Unité de Service et de Recherche CNRS-Pierre Fabre 3388, ETaC, CRDPF, 31100 Toulouse, France
| | - Elodie Rilova
- From the Unité de Service et de Recherche CNRS-Pierre Fabre 3388, ETaC, CRDPF, 31100 Toulouse, France
| | - Mohamed Amine Bouhlel
- INSERM UMR837-JPARC (Jean-Pierre Aubert Research Center), Team 4, IRCL, 59045 Lille, France
| | | | - Isabelle Dufau
- From the Unité de Service et de Recherche CNRS-Pierre Fabre 3388, ETaC, CRDPF, 31100 Toulouse, France
| | - Frédéric Ausseil
- From the Unité de Service et de Recherche CNRS-Pierre Fabre 3388, ETaC, CRDPF, 31100 Toulouse, France
| | - Antonello Mai
- Sapienza University of Rome, Department of Chemistry and Technology of Drug, Sapienza University of Rome, I-00185 Roma, Italy, Pasteur Institute-Cenci Bolognetti Foundation, Sapienza University of Rome, I-00185 Roma, Italy, and
| | - Lionel Mourey
- Institut de Pharmacologie et de Biologie Structurale (IPBS) CNRS, Toulouse, 31077, France, Université de Toulouse, UPS, IPBS, Toulouse, 31077, France
| | | | - Paola B Arimondo
- From the Unité de Service et de Recherche CNRS-Pierre Fabre 3388, ETaC, CRDPF, 31100 Toulouse, France,
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7
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Day HA, Pavlou P, Waller ZAE. i-Motif DNA: structure, stability and targeting with ligands. Bioorg Med Chem 2014; 22:4407-18. [PMID: 24957878 DOI: 10.1016/j.bmc.2014.05.047] [Citation(s) in RCA: 262] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 05/09/2014] [Accepted: 05/22/2014] [Indexed: 10/25/2022]
Abstract
i-Motifs are four-stranded DNA secondary structures which can form in sequences rich in cytosine. Stabilised by acidic conditions, they are comprised of two parallel-stranded DNA duplexes held together in an antiparallel orientation by intercalated, cytosine-cytosine(+) base pairs. By virtue of their pH dependent folding, i-motif forming DNA sequences have been used extensively as pH switches for applications in nanotechnology. Initially, i-motifs were thought to be unstable at physiological pH, which precluded substantial biological investigation. However, recent advances have shown that this is not always the case and that i-motif stability is highly dependent on factors such as sequence and environmental conditions. In this review, we discuss some of the different i-motif structures investigated to date and the factors which affect their topology, stability and dynamics. Ligands which can interact with these structures are necessary to aid investigations into the potential biological functions of i-motif DNA and herein we review the existing i-motif ligands and give our perspective on the associated challenges with targeting this structure.
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Affiliation(s)
- Henry A Day
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK
| | - Pavlos Pavlou
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK
| | - Zoë A E Waller
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK.
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8
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Kumar V, Gore KR, Pradeepkumar PI, Kesavan V. Design, synthesis, biophysical and primer extension studies of novel acyclic butyl nucleic acid (BuNA). Org Biomol Chem 2014; 11:5853-65. [PMID: 23903805 DOI: 10.1039/c3ob41244j] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A novel nucleic acid analogue called acyclic (S)-butyl nucleic acid (BuNA) composed of an acyclic backbone containing a phosphodiester linkage and bearing natural nucleobases was synthesized. Next, (S)-BuNA nucleotides were incorporated in DNA strands and their effect on duplex stability and changes in structural conformation were investigated. Circular dichroism (CD), UV-melting and non-denatured gel electrophoresis (native PAGE) studies revealed that (S)-BuNA is capable of making duplexes with its complementary strands and integration of (S)-BuNA nucleotides into DNA duplex does not alter the B-type-helical structure of the duplex. Furthermore, (S)-BuNA oligonucleotides and (S)-BuNA substituted DNA strands were studied as primer extensions by DNA polymerases. This study revealed that the acyclic scaffold is tolerated by enzymes and is therefore to some extent biocompatible.
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Affiliation(s)
- Vipin Kumar
- Chemical Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Madras (IITM), Chennai 600036, India.
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9
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El-Sayed AA, Pedersen EB, Khaireldin NA. Studying the influence of the pyrene intercalator TINA on the stability of DNA i-motifs. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2014; 31:872-9. [PMID: 23215550 DOI: 10.1080/15257770.2012.742199] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Certain cytosine-rich (C-rich) DNA sequences can fold into secondary structures as four-stranded i-motifs with hemiprotonated base pairs. Here we synthesized C-rich TINA-intercalating oligonucleotides by inserting a nonnucleotide pyrene moiety between two C-rich regions. The stability of their i-motif structures was studied by using UV melting temperature measurements and circular dichroism spectra at different pH values under noncrowding and crowding conditions (20% poly(ethylene glycol)). When TINA ((R)-3-((4-(1-pyrenylethynyl)benzyl)oxy) propane-1,2-diol) is inserted, the oligonucleotides could form an i-motif at a higher pH than observed for the corresponding wildtype oligonucleotide.
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Affiliation(s)
- Ahmed A El-Sayed
- Nucleic Acid Center, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, Denmark
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10
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Benabou S, Aviñó A, Eritja R, González C, Gargallo R. Fundamental aspects of the nucleic acid i-motif structures. RSC Adv 2014. [DOI: 10.1039/c4ra02129k] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The latest research on fundamental aspects of i-motif structures is reviewed with special attention to their hypothetical rolein vivo.
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Affiliation(s)
- S. Benabou
- Department of Analytical Chemistry
- University of Barcelona
- E-08028 Barcelona, Spain
| | - A. Aviñó
- Institute for Advanced Chemistry of Catalonia (IQAC-CSIC)
- CIBER-BBN Networking Centre on Bioengineering
- Biomaterials and Nanomedicine
- E-08034 Barcelona, Spain
| | - R. Eritja
- Institute for Advanced Chemistry of Catalonia (IQAC-CSIC)
- CIBER-BBN Networking Centre on Bioengineering
- Biomaterials and Nanomedicine
- E-08034 Barcelona, Spain
| | - C. González
- Institute of Physical Chemistry “Rocasolano”
- CSIC
- E-28006 Madrid, Spain
| | - R. Gargallo
- Department of Analytical Chemistry
- University of Barcelona
- E-08028 Barcelona, Spain
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11
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Jakobsen U, Vogel S. Assembly of liposomes controlled by triple helix formation. Bioconjug Chem 2013; 24:1485-95. [PMID: 23885785 DOI: 10.1021/bc300690m] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Attachment of DNA to the surface of different solid nanoparticles (e.g., gold and silica nanoparticles) is well established, and a number of DNA-modified solid nanoparticle systems have been applied to thermal denaturation analysis of oligonucleotides. We report herein the noncovalent immobilization of oligonucleotides on the surface of soft nanoparticles (i.e., liposomes) and the subsequent controlled assembly by DNA triple helix formation. The noncovalent approach avoids tedious surface chemistry and necessary purification procedures and can simplify and extend the available methodology for the otherwise difficult thermal denaturation analysis of complex triple helical DNA assemblies. The approach is based on lipid modified triplex forming oligonucleotides (TFOs) which control the assembly of liposomes in solution in the presence of single- or double-stranded DNA targets. The thermal denaturation analysis is monitored by ultraviolet spectroscopy at submicromolar concentrations and compared to regular thermal denaturation assays in the absence of liposomes. We report on triplex forming oligonucleotides (TFOs) based on DNA and locked nucleic acid (LNA)/DNA hybrid building blocks and different target sequences (G or C-rich) to explore the applicability of the method for different triple helical assembly modes. We demonstrate advantages and limitations of the approach and show the reversible and reproducible formation of liposome aggregates during thermal denaturation cycles. Nanoparticle tracking analysis (NTA) and dynamic light scattering (DLS) show independently from ultraviolet spectroscopy experiments the formation of liposome aggregates.
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Affiliation(s)
- Ulla Jakobsen
- Nucleic Acid Center, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark
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12
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Kumar V, Kesavan V. Acyclic butyl nucleic acid (BuNA): a novel scaffold for A-switch. RSC Adv 2013. [DOI: 10.1039/c3ra41255e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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13
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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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14
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Kutyavin IV. Use of base-modified duplex-stabilizing deoxynucleoside 5'-triphosphates to enhance the hybridization properties of primers and probes in detection polymerase chain reaction. Biochemistry 2009; 47:13666-73. [PMID: 19046073 DOI: 10.1021/bi8017784] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several base-modified duplex-stabilizing deoxyribonucleoside 5'-triphosphates (dNTPs) have been evaluated as agents for enhancing the hybridization properties of primers and probes in real-time polymerase chain reaction (PCR). It was shown that pyrimidines substituted at the 5-position with bromine or iodine atoms and methyl or propynyl groups are incorporated into PCR amplicons by Taq DNA polymerase as efficiently as natural dNTPs. The dNTP of 2-aminoadenosine was incorporated somewhat less efficiently than dATP but still supported PCR. Incorporation of these modified nucleotides into the amplified DNA represents a simple and inexpensive way to stabilize duplexes of primers and probes and is particularly effective in improving the amplification and detection of A/T-rich sequences. This technology permits the use of higher PCR annealing temperatures or alternatively a reduction in the length of the oligonucleotide components. Examples of successful application in TaqMan and Scorpion real-time detection assays are provided. Limits of the approach are identified and discussed. For example, application of the 5-bromo and 5-iodo derivatives may be limited to relatively G/C-rich DNA targets and, in particular, to those lacking long runs of adenylate and/or thymidylate. Simultaneous use of base-modified analogues of dATP and dTTP should be avoided in PCR due to "overstabilization" of the amplicon.
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15
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Jain A, Wang G, Vasquez KM. DNA triple helices: biological consequences and therapeutic potential. Biochimie 2008; 90:1117-30. [PMID: 18331847 DOI: 10.1016/j.biochi.2008.02.011] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Accepted: 02/08/2008] [Indexed: 01/25/2023]
Abstract
DNA structure is a critical element in determining its function. The DNA molecule is capable of adopting a variety of non-canonical structures, including three-stranded (i.e. triplex) structures, which will be the focus of this review. The ability to selectively modulate the activity of genes is a long-standing goal in molecular medicine. DNA triplex structures, either intermolecular triplexes formed by binding of an exogenously applied oligonucleotide to a target duplex sequence, or naturally occurring intramolecular triplexes (H-DNA) formed at endogenous mirror repeat sequences, present exploitable features that permit site-specific alteration of the genome. These structures can induce transcriptional repression and site-specific mutagenesis or recombination. Triplex-forming oligonucleotides (TFOs) can bind to duplex DNA in a sequence-specific fashion with high affinity, and can be used to direct DNA-modifying agents to selected sequences. H-DNA plays important roles in vivo and is inherently mutagenic and recombinogenic, such that elements of the H-DNA structure may be pharmacologically exploitable. In this review we discuss the biological consequences and therapeutic potential of triple helical DNA structures. We anticipate that the information provided will stimulate further investigations aimed toward improving DNA triplex-related gene targeting strategies for biotechnological and potential clinical applications.
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Affiliation(s)
- Aklank Jain
- Department of Carcinogenesis, University of Texas, M.D. Anderson Cancer Center, Science Park--Research Division, 1808 Park Road 1-C, P.O. Box 389, Smithville, TX 78957, USA
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Völker J, Klump HH, Breslauer KJ. The energetics of i-DNA tetraplex structures formed intermolecularly by d(TC5) and intramolecularly by d[(C5T3)3C5]. Biopolymers 2007; 86:136-47. [PMID: 17330895 DOI: 10.1002/bip.20712] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cytosine-rich DNA at low pH adopts an antiparallel tetraplex structure via the intercalation of two partially protonated, parallel stranded duplexes. This intriguing structural motif has been named i-DNA. We have used a combination of spectroscopic and calorimetric techniques to characterize the properties of an intermolecular i-DNA formed by d(TC(5)) and an intramolecular i-DNA formed by d[(C(5)T(3))(3)C(5)]. Our measurements reveal that both i-DNA complexes are enthalpically stabilized by 6.5-7.0 kcal/mol(base) and entropically destabilized by 20 cal/mol(base)/K. These values are about 50% larger than the corresponding enthalpy and entropy values per base for Watson and Crick duplexes and for Hoogsteen triplexes, while being similar to per base enthalpy and entropy values reported for G-quadruplexes. Our data also reveal a positive heat capacity change between 20 and 30 cal/mol(base)/K, values similar to that reported for polymeric Watson & Crick DNA duplexes. Solution-dependent studies reveal the overall thermal and thermodynamic stability of i-DNA complexes to be dictated by an interplay between pH and ionic strength. Based on the thermodynamic data measured, we discuss the feasibility of i-DNA formation in the context of conventional DNA sequences, while commenting on potential roles for this structural motif in biological regulatory mechanisms.
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Affiliation(s)
- Jens Völker
- Department of Chemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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Boutorine AS, Escudé C. Biophysical Analysis of Triple‐Helix Formation. ACTA ACUST UNITED AC 2007; Chapter 7:Unit 7.12. [DOI: 10.1002/0471142700.nc0712s29] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Seela F, Budow S, Leonard P. Oligonucleotides forming an i-motif: the pH-dependent assembly of individual strands and branched structures containing 2'-deoxy-5-propynylcytidine. Org Biomol Chem 2007; 5:1858-72. [PMID: 17551634 DOI: 10.1039/b704583b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Non-branched and branched oligonucleotides incorporating consecutive runs of 2'-deoxy-5-propynylcytidine residues () instead of 2'-deoxycytidine () were synthesized. For this, phosphoramidite building blocks of 2'-deoxy-5-propynylcytidine () were prepared using acetyl, benzoyl or N,N-di-n-butylaminomethylidene protecting groups. The formation of the i-motif assemblies incorporating 2'-deoxy-5-propynylcytidine residues was confirmed by temperature-dependent CD- and UV-spectra as well as by ion-exchange chromatography. The low pK(a)-value of nucleoside (pK(a) = 3.3) compared to dC (pK(a) = 4.5) required strong acidic conditions for i-motif formation. Branched oligonucleotide residues with strands in a parallel orientation lead to a strong stabilization of the i-motif allowing aggregation even at non-optimal pH conditions (pH = 5). The immobilization of oligonucleotides incorporating multiple residues of on 15 nm gold nanoparticles generated DNA-gold nanoparticle conjugates which are able to aggregate into i-motif structures at pH 5.
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Affiliation(s)
- Frank Seela
- Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Münster, Germany.
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Brazier JA, Fisher J, Cosstick R. Stabilization of the DNA I-Motif Structure by Incorporation of 3′-S-Phosphorothiolate Linkages. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200503110] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Brazier JA, Fisher J, Cosstick R. Stabilization of the DNA I-Motif Structure by Incorporation of 3′-S-Phosphorothiolate Linkages. Angew Chem Int Ed Engl 2006; 45:114-7. [PMID: 16299827 DOI: 10.1002/anie.200503110] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- John A Brazier
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L697ZD, UK
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McGuffie EM, Catapano CV. Design of a novel triple helix-forming oligodeoxyribonucleotide directed to the major promoter of the c-myc gene. Nucleic Acids Res 2002; 30:2701-9. [PMID: 12060688 PMCID: PMC117288 DOI: 10.1093/nar/gkf376] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Altered expression of c-myc is implicated in pathogenesis and progression of many human cancers. Triple helix-forming oligonucleotides (TFOs) directed to a polypurine/polypyrimidine sequence in a critical regulatory region near the c-myc P2 promoter have been shown to inhibit c-myc transcription in vitro and in cells. However, these guanine-rich TFOs had moderate binding affinity and required high concentrations for activity. The 23 bp myc P2 sequence is split equally into AT- and GC-rich tracts. Gel mobility analysis of a series of short TFOs directed in parallel and anti-parallel orientation to the purine strand of each tract showed that only parallel CT and anti-parallel GT TFOs formed stable triplex on the AT- and GC-rich tracts, respectively. A novel full-length GTC TFO was designed to bind simultaneously in parallel and anti-parallel orientation to the polypurine strand. Gel-shift and footprinting assays showed that the new TFO formed a triple helix in physiological conditions with significantly higher affinity than an anti-parallel TFO. Protein-binding assays showed that 1 microM GTC TFO inhibited binding of nuclear transcription factors to the P2 promoter sequence. The novel TFO can be developed into a potent antigene agent, and its design strategy applied to similar genomic sequences, thus expanding the TFO repertoire.
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Affiliation(s)
- E M McGuffie
- Department of Medicine, Division of Hematology/Oncology and Laboratory of Cancer Genomics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
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