Enrichment of RNA polII on the exon sides of exon-intron and intron-exon junctions.

(A) Enrichments of RNA polII signal at the exon side of exon-intron junctions. Normalized numbers of RNA polII Illumina reads mapped to sense and antisense strands were plotted separately. Shaded area indicates a polII-enriched region, centered at −90 bp upstream of exon-intron junctions. (B) Enrichments of RNA polII signal at the exon side of intron-exon junctions. Shaded area indicates RNA polII is devoid from a region centered at −30 bp upstream of intron-exon junctions. (C) A floating box graph comparing numbers of splicing variants for 254 genes with RNA polII pausing at exon-intron junctions with remaining genes in the Drosophila genome. The upper and lower boarders of the boxes indicate 75^th and 25^th percentiles, respectively. The upper and lower bars indicate 90^th and 10^th percentiles, respectively. Black dots are outliers beyond the 90^th and 10^th percentiles. The p value was calculated by Mann-Whitney Rank Sum test as both datasets failed a normality test (p<0.05). (D) A floating box graph comparing numbers of exons for 254 genes with RNA polII pausing at exon-intron junctions with remaining genes in the Drosophila genome. The upper and lower boarders of the boxes indicate 75^th and 25^th percentiles, respectively. The upper and lower bars indicate 90^th and 10^th percentiles, respectively. Black dots are outliers beyond the 90^th and 10^th percentiles. The p value was calculated by Mann-Whitney Rank Sum test as both datasets failed a normality test (p<0.001).