Cy5-conjugated hybridization-sensitive fluorescent oligonucleotides for ratiometric analysis of nuclear poly(A)+ RNA.

Subnuclear poly(A)(+) RNA localization in living mammalian cells was visualized by ratiometric analysis using hybridization-sensitive fluorescent oligonucleotide probes. Probes were oligonucleotides, which contained a Cy5 fluorescent dye at the strand end and a thiazole orange double-labeled nucleotide inside strand. A ratiometric analysis using poly(A)-targeting probes revealed a distribution of the probe itself as red fluorescence and localization of the target RNA sequence in cell nuclei as green fluorescence. The fluorescence of the subnuclear poly(A)(+) RNA hybridized with the poly(A)-targeting probes was observed as puncta in interchromatin areas.