Digitoxin regulates a large set of alternative cassette exons that share potential binding sites for SRp20 and Tra2-β. (A) Representative RT-PCR gels for four high-confidence hits identified by HJAY. (B) Summary of exon inclusion levels for these exons across three independent experiments. Error bars, SEM exon inclusion (PSI). (C) For digitoxin repressed exons, Tra2-β binding sites are enriched. Plotted is mean rank of all tetramers that satisfy the given consensus binding sequence. The dashed line denotes the arithmetic mean tetramer rank of 128. Motifs with a significantly altered distribution of ranks (both high and low) are denoted by an asterisk and satisfy a Wilcoxon rank-sum P-value cutoff of 0.01. (D) The same analysis for digitoxin enhanced exons show an enrichment of SRp20 sites in the upstream intron.
