Continuous growth and phosphatidylcholine synthesis of rat hepatoma cells in choline-deprived chemically defined...

A choline non-required cell line was established from a rat hepatoma cell line. The line designated R-Y121B X cho was able to grow in choline-deprived medium without serum and lipid. Choline is necessary for the biosynthesis of phosphatidylcholine, which is a main component of cell membranes. Phosphatidylcholine can be synthesized by the methylation of phosphatidylethanolamine in liver cells. Phospholipid composition and incorporation of radiolabeled serine into phosphatidylserine or phosphatidylethanolamine were quite similar in R-Y121B X cho and its parental cells. However R-Y121B X cho cells had higher phosphatidylcholine synthesis activity from radiolabeled methionine than parental cells. These results indicate that choline requirement of mammalian cells depends on the activity of phosphatidylethanolamine methyltransferase.