UDP-galactose ceramide galactosyltransferase, CGT, EC 2.4.1.45, is the key enzyme in the biosynthesis of cerebrosides and sulfatides, which are the most abundant glycosphingolipids in the myelin of the central nervous system and the peripheral nervous system. The cell-specific and highly time-regulated expression of the CGT gene is thought to play an important role in oligodendrocyte and Schwann cell differentiation. Three genomic clones encoding the mouse CGT gene were isolated and characterized. The gene is distributed over >42 kb, and the coding sequence is distributed over five exons ranging from 77 to 822 bp. Putative transcription start sites were determined by primer extension experiments. The CGT gene locus is highly conserved during evolution.