Gene structure of the murine calcium channel beta 3 subunit, cDNA and characterization of alternative splicing and transcription products

The beta 3 subunit of high-voltage-gated calcium channels is a peripheral membrane protein that copurifies with neural N-type calcium channels. Murine genomic clones containing the full coding sequence of beta 3 were isolated and the exons were mapped and sequenced. The murine calcium channel beta 3 subunit is encoded by a unique gene composed of 13 translated exons that spread over approximate to 8 kb of genomic sequence. Alternatively spliced transcripts of the beta 3 gene were identified and characterized. The primary structure of beta 3 is highly conserved between the murine, human, rabbit and rat proteins (98% identity). The intron placement within that primary structure correlates with the previously postulated exon positions in transcripts encoding the members of the calcium channel beta subunit family and confirm a close evolutionary relationship of the beta 3, beta 1, beta 2 and beta 4 subunit genes.