Localization of mRNAs for CDP-diacylglycerol synthase and phosphatidylinositol synthase in the brain and retina of developing and adult rats.

CDP-diacylglycerol (CDP-DAG) synthase (CDS) is known as one of the key enzymes in the lipid synthesis including phosphoinositides (PIs) production. Phosphatidylinositol (PtdIns) synthase (PIS) catalyzes a formation of PtdIns from CDP-DAG in the PI cycle which produces several second messengers. We compared the gene expression for a presumably PI cycle specific-CDS molecule and a PIS using Northern blot analysis and in situ hybridization histochemistry in the central nervous system (CNS) and retina of developing and mature rats. Whereas no significant expression for CDS was detected during the prenatal stage in any CNS regions, PIS mRNA had already expressed on the prenatal day 15 throughout the neuroaxis including the spinal cord. During the postnatal stages, the gene expression for both CDS and PIS was detected widely in the gray matters throughout the entire brain. The expression for CDS was at higher levels in the olfactory mitral cells, the occipital cortex, the subiculum and hippocampal CA1 pyramidal cells, and the cerebellar Purkinje cells. On the other hand, the expression for PIS was at high levels in the olfactory mitral cells, the cerebral cortex, the hippocampal and dentate neuronal layer and the cerebellar Purkinje and granule cells. No significant expression for CDS or PIS was detected in the ventricular germinal zone, the cerebellar external granular layers, the mature ependyma or entire white matters. The expression for CDS and PIS decreased slightly throughout the CNS on P49. The significance of the parallel and discrepant expression patterns in terms of relative intensity between the two enzyme molecules was discussed in relation to the membrane turnover and signal transduction.