l-DNA-tagged fluorescence in situ hybridization for highly sensitive imaging of RNAs in single cells

Abstract

We report an effective fluorescence in situ hybridization strategy, named L-DNA tagged FISH (LT-FISH), for highly sensitive RNA detection in fixed cultured cells. LT-FISH includes two-step hybridization processes with a L–D chimera oligonucleotide probe and a fluorescence-labeled PCR product tethering a L-DNA tag. The degree of fluorescence enhancement, depending on the length of PCR products, was up to 14-fold when the 606 bp product was used. Endogenous mRNA and miRNA in cancer cells were visualized by utilizing this L-DNA-mediated signal amplification technique.