Depletion of PARP1/PARylation affects transcription and PolII recovery rate as measured by nascent mRNA levels. Time-course of transcription elongation for AKAP and CAPER genes post-DRB treatment. WT and PARP1 KD cells were incubated with DRB for 3 hrs to halt transcription. Then post-DRB wash, transcription was allowed to start and continue in a synchronized manner. Levels of pre-mRNA as measured by RT-PCR using exon-intron junction primers (green arrows) were determined for AKAP200 (A) and CAPER (B) and PARP1 KD cells for AKAP200 (C) and CAPER (D). Pre-mRNA levels were normalized to the values prior of the prior-DRB treatment sample, which was set to 1. Results are shown as mean ± SEM from three independent experiments. Differences between NT and each experimental condition were considered significant according to student T-test p < 0.05.