Localization of mRNAs for synaptojanin isoforms in the brain of developing and mature rats

The localization of mRNAs for synaptojanin 1 and 2, inositol 5-phosphatases, in the brain was examined by in situ hybridization histochemistry. Synaptojanin 1 mRNA was detected in almost all neurons of the central nervous system throughout developing and mature stages, although its splicing variant (synaptojanin 1-p145-I) mRNA was expressed dominantly in forebrain and cerebellar cortex. Synaptojanin 2 mRNA was first detected in neurons of the olfactory bulb, the cerebral cortex, the hippocampus, and the cerebellar cortex on early postnatal days. As the postnatal development proceeded, the expression signal was evident in the white matters, presumptive oligodendrocytes, with the clear expression remaining in neurons of the olfactory tubercle, hippocampal pyramidal cells and cerebellar Purkinje cells.