PolyA Sequencing of K562 Cells

RNA chemical structure analysis using icSHAPE and icLASER reveals hexameric sequences that have structure differences inside and outside of cells. One such sequence that had higher in-cell reactivity was the sites of polyadenylation or PAS sequence within the 3’-UTRs. We aimed to understand this difference as we postulated it could be utilized to predict transcriptome-wide polyadenylation. To obtain direct positions with high polyadenylation sequence signal, we generated the first polyadenylation sequencing data (PAS-seq) for K562 cells. PAS-seq uses polyA tail priming to identify the sites of polyA tail selection directly. Inspection of PAS reads demonstrated clear buildup of read depth at the 3’-end of transcripts and we obtained sites of high PAS read depth and low PAS read depth. One sample