PCR validation of predicted changes in exon abundance identifies calcium-mediated splice form diversity. Microarray data detected decreases in the expression of specific exons (indicated in orange) within KCNH4, NESP55, ASL, and ATP6V0a4. For each gene, polymerase chain reaction was performed on cDNA from potassium chloride (KCl) or thapsigargin (TPG) treated cells using primers (designated by green bars) to amplify across the exon of interest. Multiple transcript variants were detected, indicating alternative splicing in the vicinity of the identified exons. Images depicting RefSeq transcript architecture were obtained through the UCSC Genome Browser [66,67]. Sequenced isoforms are indicated (*) and are represented by dark gray boxes. For ease in alignment, intron sequences are shown. The predicted sequence of the smallest ATP6V0a4 variant is shown in light gray. Isoform quantification is presented in Additional data file 9. ASL, argininosuccinate lyase; ATP6V0a4, ATPase, H+ transporting, lysosomal V0 subunit a4; KCNH4, potassium voltage-gated channel, subfamily H (eag-related), member 4; NESP55, neuroendocrine secretory protein 55.