Spatial diversity in gene expression for VDCCgamma subunit family in developing and adult mouse brains

The gamma subunit of voltage-dependent Ca2+ channels (VDCCs) is characterized by molecular diversity and regulation of AMPA-type glutamate receptors as well as VDCCs. In the present study, we examined expressions for the VDCCgamma1-8 subunit mRNAs in developing and adult mouse brains by in situ hybridization. In adult brains, the gamma2 and gamma7 subunit mRNAs were widely expressed in various grey matter regions with the highest level in cerebellar Purkinje cells and granule cells. The gamma3 and gamma8 subunit mRNAs predominated in the telencephalon, with the latter being at striking levels in the hippocampus. The gamma4 subunit mRNA was enriched in the olfactory bulb, striatum, thalamus and hypothalamus. The gamma5 subunit mRNA was abundant in the olfactory bulb, hippocampal CA2, thalamus, inferior colliculus and Bergmann glia. Transcripts of these subunits were detected in embryonic brains: some showed well-preserved spatial patterns (gamma2, gamma5, gamma7 and gamma8), while others underwent developmental up- (gamma3) or down-regulation (gamma4). In contrast, the gamma1 and gamma6 subunit mRNAs were negative or very low throughout brain development. Therefore, the present study has revealed spatial diversity in gene expression for individual VDCCgamma subunits, presumably reflecting functional diversity of this protein family and their differential involvement in neural function.