Impact of non-nucleotidic bulges on recognition of mixed-sequence dsDNA by pyrene-functionalized Invader probes

Org Biomol Chem. 2020 Jun 24;18(24):4645-4655. doi: 10.1039/d0ob01052a.

Abstract

Invader probes, i.e., DNA duplexes modified with +1 interstrand zippers of intercalator-functionalized nucleotides like 2'-O-(pyren-1-yl)methyl-RNA monomers, are energetically activated for sequence-unrestricted recognition of double-stranded DNA (dsDNA) as they are engineered to violate the neighbor exclusion principle, while displaying high affinity towards complementary DNA sequences. The impact on Invader-mediated dsDNA-recognition upon additional modification with different non-nucleotidic bulges is studied herein, based on the hypothesis that bulge-containing Invader probes will display additionally disrupted base-stacking, more extensive denaturation, and improved dsDNA-recognition efficiency. Indeed, Invader probes featuring a single central large bulge - e.g., a nonyl (C9) monomer - display improved recognition of model DNA hairpin targets vis-à-vis conventional Invader probes (C50 values ∼1.5 μM vs. ∼3.9 μM). In contrast, probes with two opposing central bulges display less favorable binding characteristics. Remarkably, C9-modified Invader probes display perfect discrimination between fully complementary dsDNA and dsDNA differing in only one of eighteen base-pairs, underscoring the high binding specificity of double-stranded probes. Cy3-labeled bulge-containing Invader probes are demonstrated to signal the presence of gender-specific DNA sequences in fluorescent in situ hybridization assays (FISH) performed under non-denaturing conditions, highlighting one potential application of dsDNA-targeting Invader probes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Cell Line
  • DNA / chemistry*
  • In Situ Hybridization, Fluorescence
  • Male
  • Molecular Probes / chemistry*
  • Nucleic Acid Denaturation
  • Pyrenes / chemistry*
  • Thermodynamics
  • Y Chromosome

Substances

  • Molecular Probes
  • Pyrenes
  • DNA
  • pyrene