1
|
Zuben de Valega Negrão CV, Cerize NN, Silva Justo-Junior AD, Liszbinski RB, Meneguetti GP, Araujo L, Rocco SA, Almeida Gonçalves KD, Cornejo DR, Leo P, Perecin C, Adamoski D, Gomes Dias SM. HER2 aptamer-conjugated iron oxide nanoparticles with PDMAEMA-b-PMPC coating for breast cancer cell identification. Nanomedicine (Lond) 2024; 19:231-254. [PMID: 38284384 DOI: 10.2217/nnm-2023-0225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2024] Open
Abstract
Aim: To synthesize HER2 aptamer-conjugated iron oxide nanoparticles with a coating of poly(2-(dimethylamino) ethyl methacrylate)-poly(2-methacryloyloxyethylphosphorylcholine) block copolymer (IONPPPs). Methods: Characterization covered molecular structure, chemical composition, thermal stability, magnetic characteristics, aptamer interaction, crystalline nature and microscopic features. Subsequent investigations focused on IONPPPs for in vitro cancer cell identification. Results: Results demonstrated high biocompatibility of the diblock copolymer with no significant toxicity up to 150 μg/ml. The facile coating process yielded the IONPP complex, featuring a 13.27 nm metal core and a 3.10 nm polymer coating. Functionalized with a HER2-targeting DNA aptamer, IONPPP enhanced recognition in HER2-amplified SKBR3 cells via magnetization separation. Conclusion: These findings underscore IONPPP's potential in cancer research and clinical applications, showcasing diagnostic efficacy and HER2 protein targeting in a proof-of-concept approach.
Collapse
Affiliation(s)
- Cyro von Zuben de Valega Negrão
- Graduate Program in Genetics & Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), 13083-864, Campinas, São Paulo, Brazil
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy & Materials (CNPEM), 13083-970, Campinas, São Paulo, Brazil
- Bionanomanufacturing Center, Institute for Technological Research (IPT), 05508-901, São Paulo, São Paulo, Brazil
| | - Natália Np Cerize
- Bionanomanufacturing Center, Institute for Technological Research (IPT), 05508-901, São Paulo, São Paulo, Brazil
| | - Amauri da Silva Justo-Junior
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy & Materials (CNPEM), 13083-970, Campinas, São Paulo, Brazil
| | - Raquel Bester Liszbinski
- Graduate Program in Genetics & Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), 13083-864, Campinas, São Paulo, Brazil
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy & Materials (CNPEM), 13083-970, Campinas, São Paulo, Brazil
| | - Giovanna Pastore Meneguetti
- Bionanomanufacturing Center, Institute for Technological Research (IPT), 05508-901, São Paulo, São Paulo, Brazil
| | - Larissa Araujo
- Bionanomanufacturing Center, Institute for Technological Research (IPT), 05508-901, São Paulo, São Paulo, Brazil
| | - Silvana A Rocco
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy & Materials (CNPEM), 13083-970, Campinas, São Paulo, Brazil
| | - Kaliandra de Almeida Gonçalves
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy & Materials (CNPEM), 13083-970, Campinas, São Paulo, Brazil
| | - Daniel R Cornejo
- Department of Materials & Mechanics, Institute of Physics, University of São Paulo, 05508-090, São Paulo, São Paulo, Brazil
| | - Patrícia Leo
- Bionanomanufacturing Center, Institute for Technological Research (IPT), 05508-901, São Paulo, São Paulo, Brazil
| | - Caio Perecin
- Bionanomanufacturing Center, Institute for Technological Research (IPT), 05508-901, São Paulo, São Paulo, Brazil
| | - Douglas Adamoski
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy & Materials (CNPEM), 13083-970, Campinas, São Paulo, Brazil
| | - Sandra M Gomes Dias
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy & Materials (CNPEM), 13083-970, Campinas, São Paulo, Brazil
| |
Collapse
|
2
|
Pleiko K, Haugas M, Parfejevs V, Pantelejevs T, Parisini E, Teesalu T, Riekstina U. Targeting triple-negative breast cancer cells with a β1-integrin binding aptamer. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 33:871-884. [PMID: 37680989 PMCID: PMC10481362 DOI: 10.1016/j.omtn.2023.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 08/14/2023] [Indexed: 09/09/2023]
Abstract
Targeted therapies have increased the treatment options for triple-negative breast cancer patients. However, the paucity of targetable biomarkers and tumor heterogeneity have limited the ability of precision-guided interventions to live up to their full potential. As affinity-targeting ligands, aptamers show high selectivity toward target molecules. Compared with antibodies, aptamers have lower molecular weight, increased stability during transportation, reduced immunogenicity, and increased tissue uptake. Recently, we reported discovery of the GreenB1 aptamer, which is internalized in cultured triple-negative MDA-MB-231 human breast cancer cells. We show that the GreenB1 aptamer specifically targets β1-integrin, a protein linked previously to breast cancer cell invasiveness and migration. Aptamer binds to β1-integrin with low nanomolar affinity. Our findings suggest potential applications for GreenB1-guided precision agents for diagnosis and therapy of cancers overexpressing β1-integrin.
Collapse
Affiliation(s)
- Karlis Pleiko
- Faculty of Medicine, University of Latvia, House of Science, Jelgavas Str. 3, 1004 Riga, Latvia
- Laboratory of Precision- and Nanomedicine, Institute of Biomedicine and Translational Medicine, University of Tartu, 50411 Tartu, Estonia
| | - Maarja Haugas
- Laboratory of Precision- and Nanomedicine, Institute of Biomedicine and Translational Medicine, University of Tartu, 50411 Tartu, Estonia
| | - Vadims Parfejevs
- Faculty of Medicine, University of Latvia, House of Science, Jelgavas Str. 3, 1004 Riga, Latvia
| | | | - Emilio Parisini
- Latvian Institute of Organic Synthesis, Aizkraukles 21, 1006 Riga, Latvia
- Department of Chemistry “G. Ciamician”, University of Bologna, Via Selmi 2, 40126 Bologna, Italy
| | - Tambet Teesalu
- Laboratory of Precision- and Nanomedicine, Institute of Biomedicine and Translational Medicine, University of Tartu, 50411 Tartu, Estonia
- Materials Research Laboratory, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Una Riekstina
- Faculty of Medicine, University of Latvia, House of Science, Jelgavas Str. 3, 1004 Riga, Latvia
| |
Collapse
|
3
|
Del Mundo IMA, Vasquez KM, Wang G. Modulation of DNA structure formation using small molecules. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2019; 1866:118539. [PMID: 31491448 PMCID: PMC6851491 DOI: 10.1016/j.bbamcr.2019.118539] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 08/20/2019] [Accepted: 08/24/2019] [Indexed: 02/06/2023]
Abstract
Genome integrity is essential for proper cell function such that genetic instability can result in cellular dysfunction and disease. Mutations in the human genome are not random, and occur more frequently at "hotspot" regions that often co-localize with sequences that have the capacity to adopt alternative (i.e. non-B) DNA structures. Non-B DNA-forming sequences are mutagenic, can stimulate the formation of DNA double-strand breaks, and are highly enriched at mutation hotspots in human cancer genomes. Thus, small molecules that can modulate the conformations of these structure-forming sequences may prove beneficial in the prevention and/or treatment of genetic diseases. Further, the development of molecular probes to interrogate the roles of non-B DNA structures in modulating DNA function, such as genetic instability in cancer etiology are warranted. Here, we discuss reported non-B DNA stabilizers, destabilizers, and probes, recent assays to identify ligands, and the potential biological applications of these DNA structure-modulating molecules.
Collapse
Affiliation(s)
- Imee M A Del Mundo
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd., Austin, TX 78723, USA
| | - Karen M Vasquez
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd., Austin, TX 78723, USA.
| | - Guliang Wang
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd., Austin, TX 78723, USA
| |
Collapse
|
4
|
del Mundo IMA, Cho EJ, Dalby KN, Vasquez KM. A tunable assay for modulators of genome-destabilizing DNA structures. Nucleic Acids Res 2019; 47:e73. [PMID: 30949695 PMCID: PMC6648359 DOI: 10.1093/nar/gkz237] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/21/2019] [Accepted: 03/25/2019] [Indexed: 11/24/2022] Open
Abstract
Regions of genomic instability are not random and often co-localize with DNA sequences that can adopt alternative DNA structures (i.e. non-B DNA, such as H-DNA). Non-B DNA-forming sequences are highly enriched at translocation breakpoints in human cancer genomes, representing an endogenous source of genetic instability. However, a further understanding of the mechanisms involved in non-B DNA-induced genetic instability is needed. Small molecules that can modulate the formation/stability of non-B DNA structures, and therefore the subsequent mutagenic outcome, represent valuable tools to study DNA structure-induced genetic instability. To this end, we have developed a tunable Förster resonance energy transfer (FRET)-based assay to detect triplex/H-DNA-destabilizing and -stabilizing ligands. The assay was designed by incorporating a fluorophore-quencher pair in a naturally-occurring H-DNA-forming sequence from a chromosomal breakpoint hotspot in the human c-MYC oncogene. By tuning triplex stability via buffer composition, the assay functions as a dual-reporter that can identify stabilizers and destabilizers, simultaneously. The assay principle was demonstrated using known triplex stabilizers, BePI and coralyne, and a complementary oligonucleotide to mimic a destabilizer, MCRa2. The potential of the assay was validated in a 384-well plate with 320 custom-assembled compounds. The discovery of novel triplex stabilizers/destabilizers may allow the regulation of genetic instability in human genomes.
Collapse
Affiliation(s)
- Imee M A del Mundo
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd. Austin, TX, USA
| | - Eun Jeong Cho
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
| | - Kevin N Dalby
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
| | - Karen M Vasquez
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd. Austin, TX, USA
| |
Collapse
|
5
|
Zhou C, Wu C, Liu Y, Wang E. Effective construction of a AuNPs–DNA system for the implementation of various advanced logic gates. RSC Adv 2016. [DOI: 10.1039/c6ra21585h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Four advanced logic gates were successfully realized under enzyme-free conditions by integration of DNA and AuNPs.
Collapse
Affiliation(s)
- Chunyang Zhou
- State Key Laboratory of Electroanalytical Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun
- China
| | - Changtong Wu
- State Key Laboratory of Electroanalytical Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun
- China
| | - Yaqing Liu
- State Key Laboratory of Electroanalytical Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun
- China
| | - Erkang Wang
- State Key Laboratory of Electroanalytical Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun
- China
| |
Collapse
|
6
|
Hégarat N, Novopashina D, Fokina AA, Boutorine AS, Venyaminova AG, Praseuth D, François JC. Monitoring DNA triplex formation using multicolor fluorescence and application to insulin-like growth factor I promoter downregulation. FEBS J 2014; 281:1417-1431. [DOI: 10.1111/febs.12714] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 12/30/2013] [Accepted: 01/08/2014] [Indexed: 01/01/2023]
Affiliation(s)
- Nadia Hégarat
- Acides nucléiques: dynamique, ciblage et fonctions biologiques; INSERM U565; Paris France
- Département Régulations, développement et diversité moléculaire; MNHN - CNRS UMR7196; Paris France
| | - Darya Novopashina
- Laboratory of RNA Chemistry; Institute of Chemical Biology and Fundamental Medicine; Siberian Division of Russian Academy of Sciences; Novosibirsk Russia
| | - Alesya A. Fokina
- Laboratory of RNA Chemistry; Institute of Chemical Biology and Fundamental Medicine; Siberian Division of Russian Academy of Sciences; Novosibirsk Russia
| | - Alexandre S. Boutorine
- Acides nucléiques: dynamique, ciblage et fonctions biologiques; INSERM U565; Paris France
- Département Régulations, développement et diversité moléculaire; MNHN - CNRS UMR7196; Paris France
| | - Alya G. Venyaminova
- Laboratory of RNA Chemistry; Institute of Chemical Biology and Fundamental Medicine; Siberian Division of Russian Academy of Sciences; Novosibirsk Russia
| | - Danièle Praseuth
- Acides nucléiques: dynamique, ciblage et fonctions biologiques; INSERM U565; Paris France
- Département Régulations, développement et diversité moléculaire; MNHN - CNRS UMR7196; Paris France
| | - Jean-Christophe François
- Acides nucléiques: dynamique, ciblage et fonctions biologiques; INSERM U565; Paris France
- Département Régulations, développement et diversité moléculaire; MNHN - CNRS UMR7196; Paris France
- Sorbonne Universités; UPMC Univ Paris 06; UMR_S 938; CDR Saint Antoine; Paris France
- Faculté de Médecine and Hôpital Saint Antoine; INSERM; UMR_S 938; CDR Saint Antoine; Paris France
| |
Collapse
|
7
|
Ikeda S, Yanagisawa H, Yuki M, Okamoto A. Fluorescent triplex-forming DNA oligonucleotides labeled with a thiazole orange dimer unit. ARTIFICIAL DNA, PNA & XNA 2013; 4:19-27. [PMID: 23445822 DOI: 10.4161/adna.24102] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Fluorescent probes for the detection of a double-stranded DNA were prepared by labeling a triplex-forming DNA oligonucleotide with a thiazole orange (TO) dimer unit. They belong to ECHO (exciton-controlled hybridization-sensitive fluorescent oligonucleotide) probes which we have previously reported. The excitonic interaction between the two TO molecules was expected to effectively suppress the background fluorescence of the probes. The applicability of the ECHO probes for the detection of double-stranded DNA was confirmed by examining the thermal stability and photophysical and kinetic properties of the DNA triplexes formed by the ECHO probes.
Collapse
Affiliation(s)
- Shuji Ikeda
- Advanced Science Institute, RIKEN, Saitama, Japan.
| | | | | | | |
Collapse
|
8
|
Kupstat A, Ritschel T, Kumke MU. Oxazine dye-conjugated dna oligonucleotides: Förster resonance energy transfer in view of molecular dye-DNA interactions. Bioconjug Chem 2011; 22:2546-57. [PMID: 22073970 DOI: 10.1021/bc200379y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In this work, the photophysical properties of two oxazine dyes (ATTO 610 and ATTO 680) covalently attached via a C6-amino linker to the 5'-end of short single-stranded as well as double-stranded DNA (ssDNA and dsDNA, respectively) of different lengths were investigated. The two oxazine dyes were chosen because of the excellent spectral overlap, the high extinction coefficients, and the high fluorescence quantum yield of ATTO 610, making them an attractive Förster resonance energy transfer (FRET) pair for bioanalytical applications in the far-red spectral range. To identify possible molecular dye-DNA interactions that cause photophysical alterations, we performed a detailed spectroscopic study, including time-resolved fluorescence anisotropy and fluorescence correlation spectroscopy measurements. As an effect of the DNA conjugation, the absorption and fluorescence maxima of both dyes were bathochromically shifted and the fluorescence decay times were increased. Moreover, the absorption of conjugated ATTO 610 was spectrally broadened, and a dual fluorescence emission was observed. Steric interactions with ssDNA as well as dsDNA were found for both dyes. The dye-DNA interactions were strengthened from ssDNA to dsDNA conjugates, pointing toward interactions with specific dsDNA domains (such as the top of the double helix). Although these interactions partially blocked the dye-linker rotation, a free (unhindered) rotational mobility of at least one dye facilitated the appropriate alignment of the transition dipole moments in doubly labeled ATTO 610/ATTO 680-dsDNA conjugates for the performance of successful FRET. Considering the high linker flexibility for the determination of the donor-acceptor distances, good accordance between theoretical and experimental FRET parameters was obtained. The considerably large Förster distance of ~7 nm recommends the application of this FRET pair not only for the detection of binding reactions between nucleic acids in living cells but also for monitoring interactions of larger biomolecules such as proteins.
Collapse
Affiliation(s)
- Annette Kupstat
- Universität Potsdam , Institut für Chemie, Physikalische Chemie, Potsdam-Golm, Germany
| | | | | |
Collapse
|
9
|
Schneider UV, Géci I, Jøhnk N, Mikkelsen ND, Pedersen EB, Lisby G. Increasing the analytical sensitivity by oligonucleotides modified with para- and ortho-twisted intercalating nucleic acids--TINA. PLoS One 2011; 6:e20565. [PMID: 21673988 PMCID: PMC3108614 DOI: 10.1371/journal.pone.0020565] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 05/04/2011] [Indexed: 11/18/2022] Open
Abstract
The sensitivity and specificity of clinical diagnostic assays using DNA hybridization techniques are limited by the dissociation of double-stranded DNA (dsDNA) antiparallel duplex helices. This situation can be improved by addition of DNA stabilizing molecules such as nucleic acid intercalators. Here, we report the synthesis of a novel ortho-Twisted Intercalating Nucleic Acid (TINA) amidite utilizing the phosphoramidite approach, and examine the stabilizing effect of ortho- and para-TINA molecules in antiparallel DNA duplex formation. In a thermal stability assay, ortho- and para-TINA molecules increased the melting point (Tm) of Watson-Crick based antiparallel DNA duplexes. The increase in Tm was greatest when the intercalators were placed at the 5′ and 3′ termini (preferable) or, if placed internally, for each half or whole helix turn. Terminally positioned TINA molecules improved analytical sensitivity in a DNA hybridization capture assay targeting the Escherichia coli rrs gene. The corresponding sequence from the Pseudomonas aeruginosa rrs gene was used as cross-reactivity control. At 150 mM ionic strength, analytical sensitivity was improved 27-fold by addition of ortho-TINA molecules and 7-fold by addition of para-TINA molecules (versus the unmodified DNA oligonucleotide), with a 4-fold increase retained at 1 M ionic strength. Both intercalators sustained the discrimination of mismatches in the dsDNA (indicated by ΔTm), unless placed directly adjacent to the mismatch – in which case they partly concealed ΔTm (most pronounced for para-TINA molecules). We anticipate that the presented rules for placement of TINA molecules will be broadly applicable in hybridization capture assays and target amplification systems.
Collapse
|
10
|
Chiou CC, Chen SW, Luo JD, Chien YT. Monitoring triplex DNA formation with fluorescence resonance energy transfer between a fluorophore-labeled probe and intercalating dyes. Anal Biochem 2011; 416:1-7. [PMID: 21609711 DOI: 10.1016/j.ab.2011.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 05/02/2011] [Accepted: 05/03/2011] [Indexed: 10/18/2022]
Abstract
Triplex-forming oligonucleotides (TFOs) are sequence-dependent DNA binders that may be useful for DNA targeting and detection. A sensitive and convenient method to monitor triplex formation by a TFO and its target DNA duplex is required for the application of TFO probes. Here we describe a novel design by which triplex formation can be monitored homogeneously without prelabeling the target duplex. The design uses a TFO probe tagged with a fluorophore that undergoes fluorescence resonance energy transfer with fluorescent dyes that intercalate into the target duplex. Through color compensation analysis, the specific emission of the TFO probe reveals the status of the triple helices. We used this method to show that triple helix formation with TFOs is magnesium dependent. We also demonstrated that the TFO probe can be used for detection of sequence variation in melting analysis and for DNA quantitation in real-time polymerase chain reaction.
Collapse
Affiliation(s)
- Chiuan-Chian Chiou
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan 333, Taiwan.
| | | | | | | |
Collapse
|
11
|
You Y, Tataurov AV, Owczarzy R. Measuring thermodynamic details of DNA hybridization using fluorescence. Biopolymers 2011; 95:472-86. [PMID: 21384337 PMCID: PMC3082624 DOI: 10.1002/bip.21615] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Revised: 01/31/2011] [Accepted: 02/21/2011] [Indexed: 11/11/2022]
Abstract
Modern real-time PCR systems make it easy to monitor fluorescence while temperature is varied for hundreds of samples in parallel, permitting high-throughput studies. We employed such system to investigate melting transitions of ordered nucleic acid structures into disordered random coils. Fluorescent dye and quencher were attached to oligonucleotides in such a way that changes of fluorescence intensity with temperature indicated progression of denaturation. When fluorescence melting data were compared with traditional ultraviolet optical experiments, commonly used dye/quencher combinations, like fluorescein and tetramethylrhodamine, showed substantial discrepancies. We have therefore screened 22 commercially available fluorophores and quenchers for their ability to reliably report annealing and melting transitions. Dependence of fluorescence on temperature and pH was also investigated. The optimal performance was observed using Texas Red or ROX dyes with Iowa Black RQ or Black Hole quenchers. These labels did not alter two-state nature of duplex melting process and provided accurate melting temperatures, free energies, enthalpies, and entropies. We also suggest a new strategy for determination of DNA duplex thermodynamics where concentration of a dye-labeled strand is kept constant and its complementary strand modified with a quencher is added at increasing excess. These methodological improvements will help build predictive models of nucleic acid hybridization. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 472–486, 2011.
Collapse
Affiliation(s)
- Yong You
- Department of Molecular Genetics and Biophysics, Integrated DNA Technologies, Coralville, IA, USA
| | | | | |
Collapse
|
12
|
Schneider UV, Mikkelsen ND, Jøhnk N, Okkels LM, Westh H, Lisby G. Optimal design of parallel triplex forming oligonucleotides containing Twisted Intercalating Nucleic Acids--TINA. Nucleic Acids Res 2010; 38:4394-403. [PMID: 20338879 PMCID: PMC2910062 DOI: 10.1093/nar/gkq188] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Twisted intercalating nucleic acid (TINA) is a novel intercalator and stabilizer of Hoogsteen type parallel triplex formations (PT). Specific design rules for position of TINA in triplex forming oligonucleotides (TFOs) have not previously been presented. We describe a complete collection of easy and robust design rules based upon more than 2500 melting points (Tm) determined by FRET. To increase the sensitivity of PT, multiple TINAs should be placed with at least 3 nt in-between or preferable one TINA for each half helixturn and/or whole helixturn. We find that ΔTm of base mismatches on PT is remarkably high (between 7.4 and 15.2°C) compared to antiparallel duplexes (between 3.8 and 9.4°C). The specificity of PT by ΔTm increases when shorter TFOs and higher pH are chosen. To increase ΔTms, base mismatches should be placed in the center of the TFO and when feasible, A, C or T to G base mismatches should be avoided. Base mismatches can be neutralized by intercalation of a TINA on each side of the base mismatch and masked by a TINA intercalating direct 3′ (preferable) or 5′ of it. We predict that TINA stabilized PT will improve the sensitivity and specificity of DNA based clinical diagnostic assays.
Collapse
Affiliation(s)
- Uffe V Schneider
- QuantiBact Inc, Department of Clinical Microbiology, Hvidovre Hospital, Kettegaards Alle 30, 2650 Hvidovre, Denmark.
| | | | | | | | | | | |
Collapse
|