Alternative Splicing of a Novel Inducible Exon Diversifies the CASK Guanylate Kinase Domain

Figure 2

Splicing analysis across the CASK gene reveals three alternative exons with divergent responses to neuronal excitation. (a) Schematic (top) illustrates CASK-001 mRNA with consecutive exons represented as alternating grey and black boxes. Inducible exons identified in this study (E18, E19, E24a) are highlighted above. Horizontal arrows represent primer sets used for RT-PCR amplification of regions spanning the exon numbers at right. (b) Gel panels show results of RT-PCR to detect splicing changes from mock (lanes M) and KCl-treated (lanes K) mouse cortical neurons. Exon regions corresponding to (a) are indicated below the gel panels, and sizes of the amplified products are indicated in base pairs (bp). Asterisks (**) indicate skipped products; unmarked bands represent included products. GAPDH transcripts were amplified as controls (lanes GAPDH). Fragment sizes, 300 and 100 bp (at left), were determined from a 100 kb DNA ladder. (c) Higher resolution analysis of the E18 and 19 region. Schematics represent initial splicing pattern and inducible change (curved arrows) for alternative exons of CASK. Numbers in parentheses represent exon sizes in base pairs. Gel panel shows triplicate measurements of the E17-18-19-20, the Δ19 and Δ18 spliced products amplified from mock (M) and KCl stimulation (K) samples. Numbers represent average % exon inclusion and standard deviations from mock (left column) and KCl (right column) datasets.