Fig 1. Principle of the fluorogenic enzyme assays.

Fluorescent dye (BODIPY FL) conjugated to RNA duplexed to anti-sense oligonucleotides is quenched by the guanine base of the guanosine nucleotide (black background) on the strand directly opposite the fluorescent dye. Enzymatic cleavage of RNA strand produces a thermodynamically unstable duplex product with low melting temperature, which dissociates at assay temperature (37°C) resulting in increased fluorescence intensity.