[DNA-protein complexes of the nuclear matrix of Ehrlich ascites carcinoma cells]

A DNA-protein complex resistant to 8 M urea and 0.1% SDS was obtained by chromatography of nuclear matrix lysate from Ehrlich ascite carcinoma cells on Sepharose 2BCL. Separation of the complex under more severe conditions (4 M guanidine hydrochloride, 5 M urea) on hydroxylapatite resulted in protein and DNA fractions, as well as in two fractions of the DNA-protein complex. One of the fractions of this complex was enriched with single-stranded DNA and contained a 5-fold excess of newly synthesized DNA over the DNA present in the original complex. The fractions isolated from the nuclear matrix of control Ehrlich ascite carcinoma cells and the cells incubated with novobiocin revealed quantitative and qualitative differences in the electrophoretic patterns of the proteins. Treatment of cells with novobiocin resulted in inhibition of DNA replicative synthesis and an increase in the protein/DNA ratio in the nuclear matrix.