Chromosomal Localization and Neural Distribution of Voltage Dependent Calcium Channel β3 Subunit Gene

Abstract

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 β3 subunit from a human genomic DNA library using VDCC β3 cDNA as a probe. We localized VDCC β3 with this genomic DNA on the chromosome by fluorescent in situ hybridization, and the distribution of VDCC β3 in the nervous system was investigated in rats by in situ hybridization histochemistry with rat VDCC β3 cDNA. The gene for the VDCC β3 was specifically localized on human chromosome 12q13. The mRNA for the VDCC β3 was predominently expressed in the nervous system. In the brain, a strong expression of VDCC β3 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 β3 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 β3 and rbE-II may function together as a pair.