Evidence for two DNA-dependent RNA polymerase activities in isolated rat-liver nuclei

Effect of the exotoxin of Bacillus thuringiensis on normal and ecdysone-stimulated ribonucleic acid polymerase activity in intact nuclei from the fat body of Sarcophaga bullata larvae

“…The incorporation of label at low ionic strength continues in a linear manner for at least 1 h and the incorporation at high ionic strength is biphasic, with a rapid incorporation for the first 0min and a slower rate between 10min and 1 h. In mammalian nuclei, the incorporation at low ionic strength ceases after approx. 10min (Widnell & Tata, 1964). Thus the substrate requirements, cation dependence and sensitivity to actinomycin and amanitin follow closely the patterns recorded for RNA polymerase activities in other eukaryotic systems (see Table 3), but the incorporation of nucleotides as a function of The assay solutions were constituted as described in the Experimental section for low ionic strength and contained 5,ug of nuclear DNA.…”

“…1-3 and in Beebee (1972) show that the properties ofthe RNA polymerase are similar to those observed in nuclei isolated from a wide range of other species (Widnell & Tata, 1964;Roeder & Rutter, 1969;Horgen & Griffin, 1971), including a related insect (Sekeris et al, 1965;Congote et al, 1969;Shaaya & Sekeris, 1971). The pattern of inhibition of the polymerase activities by a-amanitin, recorded in Table 1 Shaaya & Sekeris (1971) fornuclei from theepidermis of Calliphora erythrocephala, and is qualitatively comparable with the pattern observed in nuclei from other species.…”

Increased Activity of Chromatin-bound Ribonucleic Acid Polymerase from Soybean Hypocotyl with Spermidine and High Ionic Strength

“…Hypotheses advanced to account for high ionic strength stimulation of RNA polymerase include reinitiation (31), removal of histones (5,29), removal of an inhibitory RNA product (20), inhibition of nucleases (23), and activation of a second polymerase (35,36). Another possibility which has not been explored is suggested by the recent reports (1, 6, 22) that Mg2+ and Mn2" interact differently with the DNA template.…”

“…Although the characteristics of the chromatin-bound polymerase have been described in some detail, additional information is needed on the response to polyamines and high ionic strength. In animal nuclear and chromatin preparations there is a Mg2+-dependent RNA polymerase I which yields rRNA at low ionic strength and which is insensitive to a-amanitin (14,15,17,25,35,36). Additionally, there is an Mn2+-dependent RNA polymerase II yielding mRNA which is active at high ionic strength and is strongly inhibited by as little as 0.1 ,ug/ml of a-amanitin (14,15,17,21,25,33,35,36).…”

“…In animal nuclear and chromatin preparations there is a Mg2+-dependent RNA polymerase I which yields rRNA at low ionic strength and which is insensitive to a-amanitin (14,15,17,25,35,36). Additionally, there is an Mn2+-dependent RNA polymerase II yielding mRNA which is active at high ionic strength and is strongly inhibited by as little as 0.1 ,ug/ml of a-amanitin (14,15,17,21,25,33,35,36). The polyamine, spermidine, increases the rate of RNA synthesis by polymerases associated with animal chromatin and bacterial DNA (2, 8,19,32) Table IV, all data reported here were obtained with seedlings sprayed with 25 ml of 500 ,ug/ml 2, 4-D solution per 9-X 14-inch tray at 72 hr, and returned to the germinator for an additional 24 hr.…”