Prolonged RNA polymerase II (Pol II) elongation inhibition leads to an accumulation of Pol II, a reduction in nucleosome occupancy and recruitment of CHD1 and CHD2. (A) Chromatin immunoprecipitation sequencing (ChIP-seq) data in asynchronous cultures reflect the complex dynamics associated with cells at different stages of transcription such as the inactive off state, the initiation stage when the Pol II machinery assembles and the elongation phase following promoter escape. Elongation inhibitor 5,6-dichloro-1-β-D-ribofuranosyl-1H-benzimidazole (DRB) synchronizes transcription in cells by preventing elongation and promoter escape. (B) Prolonged DRB inhibition results in Pol II accumulation and H3 depletion at the transcription start site (TSS) of an expressed gene (NPM1) but not inactive gene (PRSS1). Pol II accumulation associates with increased CHD1 and CHD2 recruitment (significant differences between means of control and DRB tested with the students t-test, ***P <0.001).