Fig. 2

Fig. 2 Genomic organization and alternative splicing of pcdh19. (A) The pcdh19 gene comprises 5 exons distributed over 85 kb of genomic sequence. (B) The entire extracellular domain, the transmembrane domain and a short segment of cytoplasmic domain are encoded by exon 1. The remainder of the cytoplasmic domain is encoded by exons 2–5. (C) RT-PCR reveals that expression of pcdh19 begins by 6 hpf and continues through development. In addition, we observe two splice variants: a larger, major band and a shorter minor band. There does not appear to be temporal variation in the expression of the two isoforms. (D) Cloning and sequencing of the two PCR products reveals that the major band represents the full-length form of Pcdh19; we term this variant “isoform 1.” The shorter band represents the use of an alternative splice site, internal to exon 2, that deletes ∼ 70 amino acids from the cytoplasmic domain; we refer to this variant as “isoform 2.”. E, Schematic representation of the choice of alternative donor sites in exon 2.