LOCALIZATION OF MESSENGER-RNAS 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) prod uction. Phosphatidylinositol (PtdIns) synthase (PIS) catalyzes a forma tion of PtdIns from CDP-DAG in the PI cycle which produces several sec ond messengers. We compared the gene expression for a presumably PI cy cle specific-CDS molecule and a PIS using Northern blot analysis and i n situ hybridization histochemistry in the central nervous system (CNS ) and retina of developing and mature rats. Whereas no significant exp ression for CDS was detected during the prenatal stage in any CNS regi ons, PIS mRNA had already expressed on the prenatal day 15 throughout the neuroaxis including the spinal card. During the postnatal stages, the gene expression for both CDS and PIS was detected widely in the gr ay 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 Pur kinje cells. On the other hand, the expression for PIS was at high lev els in the olfactory mitral cells, the cerebral cortex, the hippocampa l and dentate neuronal layer and the cerebellar Purkinje and granule c ells. No significant expression for CDS or PIS was detected in the ven tricular germinal zone, the cerebellar external granular layers, the m ature 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 inte nsity between the two enzyme molecules was discussed in relation to th e membrane turnover and signal transduction. (C) 1998 Elsevier Science B.V. All rights reserved.