LiveArt acts as a robust reporter system for anti-cancer drug screening. (A) Representative images to show the effect of anti-cancer drugs on rRNA synthesis in clonal cells with MS2-tagged 3′-ETS-1 rRNA. Arrows point to the enriched signal of stdMCP-tdTomato. All images are maximum-intensity projections from z stacks. Scale bars, 10 µm. (B) Quantification of total MS2-tagged 3′-ETS-1 rRNA (left), ITS1 rRNA (middle), or 5.8S rRNA (right) produced per nucleus in the absence or presence of individual anti-cancer drugs. Each dot represents a single cell (n = 100). Gray line indicates mean ± SEM. (C) Workflow used to perform anti-cancer drug screening via LiveArt. (D) Statistics of MS2-tagged 5.8S rRNA accumulation revealed by the total intensity of stdMCP-tdTomato spots in the absence or presence of anti-cancer drugs, which were screened out from the library of FDA-approved drugs. Each dot represents a single cell (n = 100). Gray line indicates mean ± SEM. (E) Measurement of 45S pre-rRNA abundance. n = three technical replicates displayed as mean ± SEM.