Proximity ligation assay (PLA) with cells treated with EdU and anti-Ser5-P-RNAPII antibody; representative images with DAPI staining in blue for nuclei and PLA foci in red; cells are synchronized as Fig. 1 A and harvested at the indicated timepoints after 10 min incubation with EdU. PLA foci count in cells with >= 1 PLA foci (right panel), box-whisker plots 10–90 percentile with line at the median, Mann–Whitney t -test. n = 3, > 150 cells counted per timepoint in each repeat.
