Identification and expression of voltage-gated calcium channel β subunits in zebrafish

Voltage-gated calcium channels (VGCC) play important roles in electrically excitable cells and embryonic development. The VGCC β subunits are essential for membrane localization of the channel and exert modulatory effects on channel functions. In mammals, the VGCC β subunit gene family contains four members. In zebrafish, there appear to be seven VGCC β subunits including the previously identified β1 subunit. cDNAs for six additional VGCC β subunit homologs were identified in zebrafish, their chromosomal locations determined and their expression patterns characterized during embryonic development. These six genes are primarily expressed in the nervous system with cacnb4a also expressed in the developing heart. Sequence homology, genomic synteny and expression patterns suggest that there are three pairs of duplicate genes for β2, β3, and β4 in zebrafish with distinct expression patterns during embryonic development.