Soluble RNA Polymerases of Rat Liver Nuclei: Properties, Template Specificity, and Amanitin Responses in vitro and in vivo

Unlike the bacterial enzyme, RNA polymerase from eucaryote organisms has proved to be difficult to separate from its deoxyribonucleoprotein template, and its activity has often been measured by incubating lysed nuclei or crude aggregate nuclear preparations with the four nucleoside triphosphates required for the synthesis of RNA. Consequently, these crude enzyme preparations show activity that reflects both the amount of polymerase present and the availability of the template, and until recently this has been an impediment to studying the mode of action of hormones and other factors regulating RNA synthesis in eucaryote cells.