[Comparative study of endogenous RNA-polymerase activity of the cell nuclei and chloroplasts of pea leaves]

The endogenous RNApolymerase activity of isolated cell nuclei and chloroplasts from young pea plants (Pisum sativum) has been studied. The presence of all four nucleoside triphosphates and Mg2+ ions is necessary for the reaction. The missing of one of these nucleotides from the reaction mixture, especially ATP, sharply decreases the transcription. Chloroplasts synthesize RNA per DNA unit more intensively, than nuclei. In spring such predominance is especially pronounced. Maximal synthesis of RNA is observed at pH 8.3 both in nuclei and chloroplasts. Maximal transcription was observed at 25 degrees in chloroplasts and at 30--35 degrees in nuclei. Actinomycin D inhibited the process of transcription both in nuclei and some stimulation in chloroplasts were observed, when rifamicin B was added. It is suggested that there are differences in nuclear and chloroplast forms of RNA polymerase.