Correlation between inhibition of myelin basic protein (arginine) methyltransferase by sinefungoin and lack of compact myelin formation in cultures of cerebral cells from embryonic mice

摘要

AbstractSinefungin, a known inhibitore of protein methylation, inhibited the myelin basic protein (arginine) methyltransferase activity in homogenantes of cultured cererbral cells from embryonic mice. Fifty percent inhibition was achieved with 25μ M sinefungin. Electron microscopie examination of the myelin fraction, isolated by gradient density centifugation and obtained from untreated cells, revealed numerous ringlike multilamellaar membranous substructures that had a major dense line periodicity, compactness, and the general apperance expected of myelin obtained by the same technique from whole brain. Cells treated with 30 μM sinefungin, which inhibits myelin basic protein methyltrnasferase in broken cell preprations about 60, produced ringlike structures that were devoid of multiameller periodicity and compactness reminiscent of the vacuolated myelin observed in subacute combined degeneration and in nitrous‐oxide‐ or cycloleucine‐treated animals in which methyltransferase activity is also inhibited. The sinefungin‐induced change in multiamellar periodicity cannot be attributed to a lack of myelin basic protein, since the ratio of myelin basic protein to total protein did not decrease in sinefungin‐treated cells. This primary culture system should be useful for further evaluting the hypothesis that the methylation of mylein basic protein is related to the formation of com