[Dependence of RNA synthesis in the cell of Physarum polycephalum on concentration and activity of RNA-polymerase II].
The RNA synthesis detected by incorporation of [H3]uridine chase label proceeds in macroplasmodium and in isolated nuclei throughout the cell cycle of a synchronous myxomycetes culture of Physarum polycephalum, producing two well-shaped peaks at the postmitotic and premitotic steps. Such RNA synthesis is due to the activity of alpha-amanitin-sensitive RNA-polymerase II. Concentrations of RNA-polymerase II at various steps of the cell cycle were determined by alpha-amanitin titration; the specific activity of the enzyme was assayed. The increase in the rate of mRNA synthesis was accompanied by a rise in the concentration and specific activity of the enzyme: for the postmitotic peak, for instance, the corresponding values were about 2-2.5 and 2-4 times as high as minimum values revealed during the cycle. The results obtained are discussed in terms of transcription control in eukaryotic systems.
D000546:Amanitins / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D007700:Kinetics; D010804:Physarum / Q000201:enzymology*; D012319:RNA Polymerase II / Q000378:metabolism*; D012331:RNA, Fungal / Q000096:biosynthesis*; D014158:Transcription, Genetic
D000546:Amanitins; D012331:RNA, Fungal; D012319:RNA Polymerase II; D012321:DNA-Directed RNA Polymerases
Sintez RNK v kletochnom tsikle Physarum polycephalum v zavisimosti kontsentratsii i udel'noĭ aktivnosti RNK-polimerazy II.