Fig. 3.

RNAP2 pause-release in signal-induced gene expression. a VEGFA-stimulated changes in gene expression in HUVECs [21]. VEGFA-responsive genes were clustered into three groups by the temporal pattern of their VEGFA-induced expression change (see “Methods”). b Both the responsive and non-responsive (genes expressed during the time course without a significant change) gene sets had RNAP2 pre-loaded and paused prior to VEGFA-stimulation. c–f Genes responsive (red line) to VEGF (c), IL4 (d), or TNFα (e, f) overall had lower PI compared to genes non-responsive (black line) to each stimulus. “Primary responsive genes” (f) were defined as those that respond in the presence of the protein synthesis inhibitor cycloheximide (***p <0.001; Mann–Whitney U test.) g, h VEGFA rapidly induced overall pause-release among early upregulated genes (g) but not late upregulated genes (h). i Pause-release is required for rapid signal-induced gene expression. Treatment of HUVECs with pause-release inhibitor FP markedly attenuated VEGFA activation of early upregulated genes. FP had more moderate effects on VEGFA activation of late upregulated genes