Differential expression of mRNAs encoding gamma and delta subunits of Ca2+/calmodulin-dependent protein kinase type II (CaM kinase II) in the mature and postnatally developing rat brain.

The expression of mRNAs encoding gamma and delta subunits of Ca2+/calmodulin-dependent protein kinase type II (CaM kinase II) in the brain of mature and postnatally developing rats was examined by in situ hybridization histochemistry. At the adult stage, mRNAs for both subunits were expressed in the olfactory bulb, and piriform cortex. The cerebral neocortex expressed the gamma subunit mRNA evenly through the layers II to VI at a moderate level, whereas the delta subunit mRNA was expressed in a distinctly laminar distribution. The hippocampal pyramidal and dentate granule cells expressed the gamma subunit mRNA intensely without any significant expression signals for the delta subunit. In the cerebellum, moderate expression signals for the gamma subunit were confined to the Purkinje cell layer, while intense expression signals for the delta subunit were detected in the cerebellar granule cell layer, without any significant expression signals in the Purkinje cell layer. In the spinal cord, mRNA for the gamma subunit was expressed in neurons throughout the gray matter, while the expression of mRNA for the delta subunit was confined to neurons in laminae I and IX. The expression pattern of genes for both subunits was basically accomplished at birth with lower intensity, except for the striatum and cerebellar Purkinje cells, which transiently expressed mRNA for the gamma and delta subunits, respectively, at birth. These results indicate that the expression of genes for each of the subunits of CaM kinase II is differentially regulated in various brain regions and that the individual subunits are involved in differential functions in mature and developing rat brain.