Long Chain Fatty Acid Formation: Key Step in Myelination studied in Mutant Mice

MYELIN is the most stable membrane known and the fact that it contains ten times as much long chain sphingolipid as any other known membrane structure has led to the suggestion that the long chain fatty acids (> 18 carbon atoms) in these sphingolipids are concerned in the stability of myelin 1,2 . The finding 3,4 of a myelin deficient mouse mutant whose galactolipids and sphingomyelin lack long chain fatty acids led us to investigate whether the elaboration of long chain sphingolipid molecules is a key step in myelin formation. The comparison of histological and biochemical events related to myelination in normal and myelin deficient mutant mice supports the hypothesis that in the events leading to adult myelin, the appearance of fatty acids with 24 carbon atoms follows the appearance of cerebrosides and sulphatides in myelin.