Neuronal localization in the rat brain of the messenger RNA encoding calcyphosine, a new calcium-binding protein

The cDNA encoding calcyphosine, a new calcium-binding protein of the calmodulin superfamily which is regulated by cAMP, has been cloned in the dog thyroid (EMBO J., 8 (1989) 111–116). By in situ hybridization with synthetic oligonucleotides, we here demonstrate for the first time its neuronal localization in the rat brain. Hybridization signal was detected in all the olfactory areas; in pyramidal and non pyramidal-shaped neurons in the different layers of the cerebral cortex, especially the superficial ones; in the pyramidal cells of the different sectors of the Ammon's horn and in the granule cells of the dentate gyrus of the hippocampus; in the subiculum; in the medium-sized and large neurons of the different quadrants of the caudate-putamen and accumbens and in the cerebellar Purkinje cells. Hybridization was also observed to a lesser extent in the majority of the neurons in the basal areas of the forebrain, including septum, nucleus of the diagonal band and amygdala; in the globus pallidus, entopeduncular nucleus, substantia nigra pars reticulata and compacta, ventral tegmental area; in the subthalamic nucleus; in the thalamus; in the hypothalamus; in the brainstem and in the upper cervical spinal cord. In addition to its neuronal localization, calcyphosine mRNA was also found in ependymal cells. The non-detection of positive cells in the white matter was not in favor of prominent glial localization, although it does not exclude it.