[Bromodeoxyuridine-induced weakening of DNA--protein interaction in chromatin according to nucleoprotein--celite chromatography].

After incorporation into DNA the thymidine analogue bromodeoxyuridine (BUDR) changes the cell phenotype, inhibiting specialized cellular functions. The biological activity of BUDR is suggested to be underlain by certain changes in DNA-protein interactions. It was shown by nucleo-protein-celite chromatography (NPC chromatography) of unfractionated cell lysates that interactions of BUDR-substituted DNA with proteins in Rauscher erythroleukemic cells are actually modified. In contrast to current views suggesting a strengthening of DNA-protein bonds in BUDR-treated cells, they are in fact relaxed. Rapidly labelled heterogeneous nuclear RNAs are divided by NPC chromatography into three subpopulations. The relative rates of their synthesis are significantly changed after BUDR treatment of erythroleukemic cells.