CHROMOSOMAL LOCALIZATION AND NEURAL DISTRIBUTION OF VOLTAGE-DEPENDENTCALCIUM-CHANNEL B-3 SUBUNIT GENE

Voltage dependent calcium channel (VDCC) mediates the influx of free c alcium ions that acts as a signal transducer. The beta 3 subunit of th e VDCC regulates the activation (opening) and inactivation (Closing) k inetics through phosphorylation/dephosphorylation. We isolated a genom ic clone of the human VDCC beta(3) subunit from a human genomic DNA li brary using VDCC beta(3) cDNA as a probe. We localized VDCC beta(3) wi th this genomic DNA on the chromosome by fluorescent in situ hybridiza tion, and the distribution of VDCC beta(3) in the nervous system was i nvestigated in rats by in situ hybridization histochemistry with rat V DCC beta(3) cDNA. The gene for the VDCC beta(3) was specifically local ized on human chromosome 12q13. The mRNA for the VDCC beta(3) was pred ominently expressed in the nervous system. In the brain, a strong expr ession of VDCC beta(3) mRNA was found in the medial habenular nucleus, a high level of expression was observed in the olfactory bulb and cer ebellum, and a relatively high level of VDCC beta(3) mRNA was localize d in the cerebral cortex, caudate-putamen and hippocampal formation. I nterestingly, 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.