Oligonucleotide-conjugated thiazole orange probes as "light-up" probes formessenger ribonucleic acid molecules in living cells

"Light-up" probes, icosa-alpha -thymidylate-thiazole orange conjugates, for the in situ time-resolved detection of messenger ribonucleic acid (mRNA) i n living cells are evaluated. Upon annealing with polyA in aqueous, solutio ns, the icosa-alpha -thymidylate-thiazole orange conjugates were shown to b e up to 15 times more fluorescent. Microinjection of these probes inta adhe rent fibroblasts, resulted in high yields of hybridization and fluorescent signals. Incubation of cells in the presence of these probes resulted in fa cile internalization of the probe and similar painting of the messenger RNA in the nuclear and cytosolic regions.