Alternative splicing of G6b in platelets. (A) The G6b (c6orf25) gene consists of 6 exons, with the fifth exon containing 2 potential splice acceptor sites (exon 5a or 5b). (B) Seven splice variants of the G6b transcript are annotated in the Entrez Gene database. Transcripts encoding G6b-F and -G contain the intronic sequences IV and V, respectively. Splice variant-specific primer binding sites are represented by arrows. (C) RT-PCR was used to determine which G6b transcripts are expressed in platelets. The reverse primer G6b-A/C/G potentially amplifies G6b-A, -C, and -G (lane 2); however, only G6b-A is detected because the 457-bp band corresponding to G6b-C is not observed nor is any band detected with the G6b-G–specific primer (lane 7). G6b-B (lane 3) is the only other splice variant detected. Expected sizes of PCR products are shown in Table 4.