Figure 3. Termination is fast while release into elongation explains variability of Pol II turnover at pause sites.

(A) Representation of pausing kinetics under steady-state and flavopiridol-inhibited conditions. The steady-state observed turnover (${\widehat{k}}_{\text{obs}}$)is the sum of the rates of release into elongation (${\widehat{k}}_{\text{rel}}$) and premature termination (${\widehat{k}}_{\text{term}}$). Upon flavopiridol inhibition, observed turnover is caused only by premature termination.

(B) The distribution of the first-order rate constants for total turnover, release into elongation, and premature termination.

(C) Metaplots of TT-TL-seq signal grouped into even quartiles by release and termination of the respective high confidence TSS (n = 2422 genes). Coverage is determined over 50 nt bins.

(D) Total observed rate constant plotted versus the log₂ ratio of the release rate and termination rate. Points are colored if the 80% credible interval of the log₂ ratio does not overlap zero and the median value is greater than 1 (blue) or less than −1 (red).