A possible role of lipids in RNA polymerase from mammalian cells.

Abstract

The effects of treatment with phospholipases and extraction with solvents on the activities of RNA polymerases from several rat tissues were studied. The RNA polymerase activity of particulate enzyme from rat liver nuclei was decreased by pretreatment of the enzyme with phospholipase A. The phospholipase decreased the RNA polymerase activity in presence of Mg2+ but not that in presence of Mn2+. The effect of phospholipase A was observed only at low ionic concentration. When the RNA polymerase activity was determined in presence of ammonium sulfate, KCl, or NaCl, phospholipase A did not decrease the RNA polymerase activity. Extraction of the RNA polymerase with ether or iso-octane decreased the RNA polymerase activity to approximately the same extent as the pretreatment with phospholipase A. Phospholipase C produced similar changes as phospholipase A but phospholipase D and lipase did not have any effect on the RNA polymerase activity. Treatment with phospholipase A as well as extraction with solvents enhanced the activity of chromatin-bound RNA polymerase from rat brain, and the RNA polymerase activities of similar preparations from spleen, kidney, heart, and lung were affected only to a relatively smaller extent.