SUBUNITS OF MAMMAL DNA DEPENDENT RNA POLYMERASE III MODIFIED IN VIVO
N.A. Merkulova,1 V.M. Sedova 1,2,*
1 Institute of Cytology RAS, St. Petersburg, and 1 Department of Medical Physics,
St. Petersburg State Polytechnical University;
* e-mail: vandasedova@rambler.ru
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.
Key words:
RNA Polymerase III, phosphorylation, glycosylation, human placenta and A431 cells, mouse fibroblasts
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