Danko et al. studied the kinetics of RNA polymerase II (Pol II)-dependent transcription elongation using global run-on sequencing. They found that the elongation rate of the same gene differed between cell lines and in response to tumour necrosis factor (TNF) or 17β-oestradiol, and it increased as transcription progressed. Furthermore, an increased elongation rate correlated with a higher density of Pol II at genes, which translated to higher rates of mRNA production. The authors also determined how TNF and 17β-oestradiol influence Pol II kinetics to stimulate gene expression; TNF promoted the release of paused Pol II at target genes, whereas 17β-oestradiol increased Pol II initiation. So, during transcription, elongation rate is variable, and the kinetics of Pol II initiation, pausing and elongation can be influenced by signalling pathways.