EXPRESSION OF THE CERAMIDE GALACTOSYLTRANSFERASE GENE DURING MYELINATION OF THE MOUSE NERVOUS-SYSTEM - COMPARISON WITH THE GENES ENCODING MYELIN BASIC-PROTEINS CHOLINE KINASE AND CTP-PHOSPHOCHOLINE CYTIDYLYLTRANSFERASE

The present study documents the patterns of mRNA expression for the ce ramide galactosyltransferase (CGT), the CTP:phosphocholine cytidylyltr ansferase (CT), and the choline kinase (CK) during the myelination per iod of the mouse central nervous system (CNS) and peripheral nervous s ystem (PNS). Using the Northern blot technique with densitometric anal yses, we show that the CK gene is not developmentally regulated during the period studied, whereas a peak of expression of the CT gene is ob served around day 10. On the other hand, the expression of the CGT gen e is similar to that of the MBP gene in the CNS and the PNS. Therefore , the synthesis of the galactosylceramides during the myelination peri od seems to be controlled at the level of the expression of the CGT ge ne. These results were compared to those of a neurological mutant, the trembler mouse, whose PNS myelination is deficient. Our results clear ly indicate that the deficit in the accumulation of the galactosylcera mides documented for this mutant is well corelated to a reduced CGT ge ne expression.