Figure 2:

(A) Estimated range of RNA half-lives in mammalian cells based on data from (Schofield et al., 2018; Schwalb et al., 2016; Yang et al., 2003). (B) Simulation of RNA decay rates for a s⁴U pulse-chase experiment for three different RNA half-lives, represented as a fraction of the total amount of s⁴U-labeled RNA at the start of the chase. (C) Simulation of s⁴U approach-to-equilibrium kinetics for three different RNA half-lives. (D) Kinetics of s⁴U incorporation during 5 min of s⁴U labeling for a transient RNA (t_1/2 = 5 min) and two mRNAs (t_1/2 = 0.5h and 4h).