Ethynyl-labeled cytidine (5-EC) can be used as a replacement for BrU (5-Bromo-uridine) to measure de novo RNA synthesis in proliferating cells. 5-EC is cell permeable and incorporates into nascent RNA instead of its natural analog cytidine. The resulting ethynyl-functionalized RNA can subsequently be detected via Cu(I)-catalyzed click chemistry that offers the choice to introduce a Biotin group (via Azides of Biotin) for subsequent purification tasks or a fluorescent group (via Azides of fluorescent dyes) for subsequent microscopic imaging.
