Isolation of Nucleoli and Localization of Ribonucleic Acid Polymerase I from Soybean Hypocotyl

An effective method for the isolation of nucleoli from auxin-treated soybean (Glycine max, var. Wayne) hypocotyl was developed by polytron homogenization and sucrose gradient centrifugation. The nucleoli expressed only the alpha-amanitin-insensitive RNA synthetic activity. This activity chromatographed as RNA polymerase I on DEAE-cellulose. It appears that the plant nucleolus, like the animal nucleolus, is the site of localization for RNA polymerase I.