title: Robust strand exchange reactions for the sequence-specific, real-time detection of nucleic acid amplicons.
abstract: Loop-mediated isothermal amplification (LAMP) of DNA is a powerful isothermal nucleic acid amplification method that can generate upward of 10(9) copies from less than 100 copies of template DNA within an hour. Unfortunately, although the amplification reactions are extremely powerful, real-time and specific detection of LAMP products remains analytically challenging. In order to both improve the specificity of LAMP detection and to make readout simpler and more reliable, we have replaced the intercalating dye typically used for monitoring in real-time fluorescence with a toehold-mediated strand exchange reaction termed one-step strand displacement (OSD). Due to the inherent sequence specificity of toehold-mediated strand exchange, the OSD reporter could successfully distinguish side products from true amplicons arising from templates corresponding to the biomedically relevant M. tuberculosis RNA polymerase (rpoB) and the melanoma-related biomarker BRAF. OSD allowed the Yes/No detection of rpoB in a complex mixture such as synthetic sputum and also demonstrated single nucleotide specificity in Yes/No detection of a mutant BRAF allele (V600E) in the presence of 20-fold more of the wild-type gene. Real-time detection of different genes in multiplex LAMP reactions also proved possible. The development of simple, readily designed, modular equivalents of TaqMan probes for isothermal amplification reactions should generally improve the applicability of these reactions and may eventually assist with the development of point-of-care tests.
authors.affiliation: †Center for Systems and Synthetic Biology, ‡Department of Chemistry, §Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712, United States.
authors.forename: Yu Sherry
authors.initials: YS
authors.lastname: Jiang
authors.affiliation: †Center for Systems and Synthetic Biology, ‡Department of Chemistry, §Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712, United States.
authors.forename: Sanchita
authors.initials: S
authors.lastname: Bhadra
authors.affiliation: †Center for Systems and Synthetic Biology, ‡Department of Chemistry, §Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712, United States.
authors.forename: Bingling
authors.initials: B
authors.lastname: Li
authors.affiliation: †Center for Systems and Synthetic Biology, ‡Department of Chemistry, §Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712, United States.
authors.forename: Yuefeng Rose
authors.initials: YR
authors.lastname: Wu
authors.affiliation: †Center for Systems and Synthetic Biology, ‡Department of Chemistry, §Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712, United States.
authors.forename: John N
authors.initials: JN
authors.lastname: Milligan
authors.affiliation: †Center for Systems and Synthetic Biology, ‡Department of Chemistry, §Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712, United States.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Ellington
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000737:chemistry* / Q000235:genetics*; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D020641:Polymorphism, Single Nucleotide; D012313:RNA / Q000737:chemistry* / Q000235:genetics*; D013183:Sputum / Q000382:microbiology; D013997:Time Factors
chemical_list: D015342:DNA Probes; D012313:RNA; D004247:DNA