Application of caged fluorescent nucleotides to live-cell RNA imaging

A caged fluorescent nucleic acid probe, which contains a nucleotide modified with one photolabile nitrobenzyl unit and two hybridization-sensitive thiazole orange units, has been synthesized for area-specific fluorescence imaging of RNA in a cell. The probe emits very weak fluorescence regardless of the presence of the complementary RNA, whereas it shows hybridization-sensitive fluorescence emission after photoirradiation for uncaging. Such probes are generated via several chemical synthetic steps and are applicable to area-specific RNA imaging in a cell. Only probes that exist in the defined irradiation area are activated via uncaging irradiation.