Methods of mRNA stability tests such as transcription inhibition initially are proved most amenable for high-throughput technologies. Actinomycin D is a fast-acting DNA intercalator which is widely used as a transcription inhibitor to achieve mRNA inhibition in mRNA stability assays. The level of an mRNA transcript could be quantified to measure the half-life of specific mRNAs either when the mRNA is in a steady-state or after the inhibition of mRNA synthesis by actinomycin D.

https://mrna.creative-biolabs.com/actinomycin-d-based-method.htm