title: DNA dependent RNA polymerase from Ehrlich ascites tumor cells. V. Characterization of a factor repressing RNA polymerase II as a ribonucleoprotein.
abstract: Previously we reported the isolation of a factor, named the R-protein, which strongly repressed RNA polymerase II [EC 2.7.7.6] of Ehrlich ascites tumor cells. In the present work this factor was found to contain much RNA (ratio of RNA to protein, 2.3 to 1). The RNA was G:C rich, with a very high content of guanylic acid (about 38%). On equilibrium density gradient centrifugation in Cs2SO4 solution, the RNA became distributed above free RNA, but after digestion of the R-protein with pronase the RNA cosedimented with free RNA. Thus the R-protein is a complex of RNA and protein.
mesh_terms: D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000201:enzymology*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D051379:Mice; D009363:Neoplasm Proteins / Q000502:physiology*; D012265:Ribonucleotides / Q000032:analysis; D013056:Spectrophotometry, Ultraviolet
chemical_list: D009363:Neoplasm Proteins; D012265:Ribonucleotides; D012321:DNA-Directed RNA Polymerases