[SUBUNITS OF MAMMAL DNA DEPENDENT RNA POLYMERASE III MODIFIED IN VIVO].

In subfractions of DNA-dependent RNA polymerase isolated from nuclei of 3T3 mouse fibroblasts, A431 epidermoid carcinoma cells and mature human placenta, we have identified three subunits modified by both phosphorylation and O-N-acetylglucosamine glucosilation. The subfractions of the human enzyme contained modified subunits with molecular weight of 60 and 45 kDa and a subunit of 52 kDa probably belonging to one of the basal factors of RNA Polymerase III transcription. The subfractions of 3T3 mouse cells RNA Polymerase III consisted of modificated subunits with molecular weight 49, 45 and 42 kDa, however, the 45 kDa subunit might be a component of the basal transcription factor of RNA Polymerase III, since it was not identified in mouse enzyme composition.

[Dynamic phosphorylation of RNA polymerase III holoenzyme subunits from human epidermoid carcinoma cells A431 cultivated under different conditions].

Dynamic phosphorylation in vivo of individual subunits of holoenzyme RNA polymerase III subfractions IIIa and IIIb on serine/threonine and tyrosine aminoacid residues has been shown in human epidermoid carcinoma cells A431. Cells cultivation under starvation on embryonic serum caused a prolongation of the cell cycle, while cultivation at low concentration of epidermal growth factor (EGF) activated cell proliferation. Subunit 45 kDa is phosphorylated on serine/threonine residues in subfraction IIIa only in starving cells.

[Subunits of human holoenzyme of DNA dependent RNA polymerase III phosphorylated in vivo].

Phosphorylation of human holoenzyme of DNA dependent RNA polymerase III subunits in vivo has been investigated. RNA polymerase III from human placenta nuclei and epidermoid carcinoma cells A431 was isolated as two subfractions (IIIa and IIIb) distinguished in the order of elution from DEAE Sephadex A-25 column chromatography and buoyant density at glycerol gradient centrifugation. The subfractions of RNA polymerase III holoenzyme consists of four subunits with molecular masses 60, 52, 45 and 38 kDa, respectively, phosphorylated in vivo.

Antiarrhythmic activity of 4,6-di(het)aryl-5-nitro-3,4-dihydropyrimidin-(1H)-2-ones and its effects on arterial pressure in rats.

The antiarrhythmic activity of 4,6-di(het)aryl-5-nitro-3,4-dihydropyrimidin-(1H)-2-ones toward two types of experimental rat arrhythmia has been studied. With CaCl(2) induced arrhythmia model, several agents have demonstrated high antiarrhythmic activity and the lack of influence on arterial pressure of rats.

Small stable RNA level depends on the physiological state of the cell.

The level of 5S rRNA and tRNAi(Met)1 synthesized by RNA polymerase III was investigated in human epidermoid carcinoma cells A431 at different physiological states: low and high proliferation and apoptosis. The real-time RT-PCR method using SYBR Green I was applied to measure certain RNA species in total cellular RNA. The share of 5S rRNA was practically the same in slowly and actively proliferating A431 cells, but increased about 2.