Platelet transcripts are capped, tailed, and spliced. (A) The techniques we have used to capture and concentrate poly-A mRNA or 5′-capped mRNA from platelets. The captured RNAs are concentrated by immunoprecipitation techniques. For poly-A pull-down, the bead-conjugated oligo-dT sequence binds to the poly-A tail. For the 5′-cap pull-down, a bead-conjugated hyperaffinity mutant enzyme binds to the 7mG cap at the 5′ end of the mRNA. (B) Bar graph of the RNA-seq expression estimates (RPKM) of a histone transcript HIST1H4B and the transcript coding for the platelet thrombin receptor protease-activated receptor 1 (F2R) following mRNA isolation by a 5′-cap or poly-A tail pull-down. (C) RNA-seq coverage graph of FBJ murine osteosarcoma viral oncogene homolog B (FOSB), which appears mostly unspliced in platelets. Note that reads align to both exons and introns. Compare this with GP9 in Figure 2, which has very few reads mapping to introns. RPKM, read (or fragment) per kilobase normalized to a million.