[Comparison of endogenous nuclear RNA-polymerase II at different stages of mycoplasmodial growth].

The nuclei of Physarum polycephalum isolated from the 48- and 96-hour-old growing microplasmodium differ 7-8 fold by the rates of [3H]UTP incorporation in vitro accompanied by a slight (approximately 1.6 fold) change in concentration of endogenous RNA-polymerase II. Using mild fragmentation of chromatin nuclei by micrococcal nuclease and DEAE-Sephadex chromatography the bound enzyme was shown to consist of two forms differing in the degree of their binding to the template and in functional significance. Transcription in the Physarum polycephalum nuclei can be regulated by changes in the correlation of these forms.