Chromosomal localization and neural distribution of voltage dependent calcium channel beta 3 subunit gene

Voltage dependent calcium channel (VDCC) mediates the influx of free calcium ions that acts as a signal transducer. The beta 3 subunit of the VDCC regulates the activation (opening) and inactivation (closing) kinetics through phosphorylation/dephosphorylation. We isolated a genomic clone of the human VDCC beta 3 subunit from a human genomic DNA library using VDCC beta 3 cDNA as a probe. We localized VDCC beta 3 with this genomic DNA on the chromosome by fluorescent in situ hybridization, and the distribution of VDCC beta 3 in the nervous system was investigated in rats by in situ hybridization histochemistry with rat VDCC beta 3 cDNA. The gene for the VDCC beta 3 was specifically localized on human chromosome 12q13. The mRNA for the VDCC beta 3 was predominantly expressed in the nervous system. In the brain, a strong expression of VDCC beta 3 mRNA was found in the medial habenular nucleus, a high level of expression was observed in the olfactory bulb and cerebellum, and a relatively high level of VDCC beta 3 mRNA was localized in the cerebral cortex, caudate-putamen and hippocampal formation. Interestingly, this distribution pattern is very similar to that of the rbE-II, mid-low VDCC 1 subunit, and it is suspected that VDCC beta 3 and rbE-II may function together as a pair.