Genome binding/occupancy profiling by high throughput sequencing Other
Summary
Using pol II mutants in human cells we found that slow transcription repositioned specific co-transcriptionally deposited chromatin modifications; H3K36me3 shifted within genes toward 5’ ends and H3K4me2 extended further upstream of start sites. Slow transcription also evoked a hyperphosphorylation of CTD Ser2 residues at 5’ ends of genes that is conserved in yeast. We propose a “dwell-time in the target zone” model to explain the effects of transcriptional dynamics on establishment of co-transcriptionally deposited protein modifications. Promoter-proximal Ser2 phosphorylation is associated with longer pol II dwell time at start sites and reduced transcriptional polarity due to strongly enhanced divergent antisense transcription at promoters.
Overall design
The effect of transcription elongation rate on histone H3K36me3, H3K4me2 and pol II CTD phosphorylation was analyzed by ChIP-seq in isogenic human HEK293 cell lines that inducibly express a-amanitin resistant mutants of the RNA polymerase II large subunit with slow elongation rates. Anti-pol II total nascent RNA sequencing (tNET-seq) was developed to assay transcription by WT and slow pol II. Slow pol II mutants in S. cerevisiae were also assayed for pol II CTD Ser2 phosphorylation.