Platelet transcripts have variable 5′ or 3′ UTRs. (A) Shown are coverage graphs of the 5′ end of GFI1B in platelets. The top panel represents coverage of all reads mapping to the 5′ end of GFI1B. The red box is drawn around the region that maps beyond the known transcript annotation (blue). The bottom panels show only those reads that contain the sequence tag ligated onto the 5′ end at time of sample preparation (for details, see Osman et al²³ ). The 5′-tagged reads are only the extreme 5′-terminal reads and therefore mark the transcription start site. (B) Coverage graph of the 3′ end of purinergic receptor P2Y, G-protein coupled 1 (P2RY1) in platelets. The red box is drawn around the region that maps beyond the known 3′ UTR annotation. miRNA target analysis of this additional sequence identified several miRNA binding sites. A representative subset of the target sites is marked underneath the graph. See it yourself: To see GFI1B and P2RY1 in platelets via the UCSC Genome Browser, follow the Web link > access instructions for site 1 (see Table 1). For individual reads, follow the Web link > access instructions for site 2 (see Table 1). Search for GFI1B or P2RY1 in the browser. Note that the 5′-terminal reads in the bottom panels of A were processed from the data set published by Osman et al²³  and are therefore not yet available in a browser-friendly format.