Effect of phospholipid vesicles on endogenous RNA polymerase activity of isolated rat liver nuclei

Negatively charged phosphatidylserine vesicles increase RNA polymerase activity of isolated rat liver nuclei, whereas inhibition is obtained with sphingomyelin, phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol vesicles. The effect of phosphatidylserine on template activity is dose-dependent and similar to that reported for acidic polymers like heparin. These data indicate that the nature of the polar head is mainly responsible for the different effects and suggest that the phospholipids may be involved in mediating gene expression.