Tissue-specific expression of splice variants of the mouse voltage-gated calcium channel alpha 2/delta subunit

Five different splice variants of mouse alpha 2/delta subunit isoforms (alpha 2a-e), which arose from various combinations of three alternatively spliced regions, were cloned with a combination of cDNA library screening and RT-PCR, Expression patterns and relative abundance of the various isoforms in mouse tissues were determined with an RNAse protection assay, Skeletal muscle and brain expressed single isoforms, alpha 2a and alpha 2b, respectively; however, the cardiovascular system expressed all five isoforms, Heart expressed mainly isoforms alpha 2c and alpha 2d while, in contrast to other species, aorta expressed predominantly alpha 2a, the 'skeletal muscle' isoform. Smooth muscle-containing tissues expressed alpha 2d and alpha 2e. Thus, alpha 2/delta isoforms are restricted in their tissue expression, suggesting an important functional role for the differentially spliced variants.