Ptprc intron retention correlates with hnRNPLL expression in wild-type T cells and low expression in B cells. (a) CD19+ B cells (blue traces), which have naturally low expression of Hrnpll, display decreased intron retention compared with CD4+ T cells. The schematic diagram shows RNA-seq data prepared from three independent samples of wild-type lymphocytes enriched by magnetic beads for CD4+ T cells or CD19+ B cells. The difference in intron and exon read depths between T and B cells is shown in purple. (b) The pattern of decreased intron retention is recapitulated in an independent RNA-seq dataset from the ImmGen project  for wild-type T and B cells purified by fluorescence-activated cell sorting. T cells (red trace) show increased read depths over introns flanking the alternative exons of Ptprc, compared with B cells (blue trace). The difference in read depth over introns and exons is indicated by the purple trace.