[Characterization of the nuclease-sensitive chromatin regions from N-nitrosodiethylamine-induced hepatoma cells]

Protein-DNA complexes released from chromatin of the intact rat liver and hepatoma induced by N-diethylnitrosamine during nuclease digestion have been subdivided into two groups of high and low molecular weight. Immunoreactive proteins are concentrated mainly in high molecular complexes. Immunoblotting of proteins from the nuclease-sensitive regions of normal and tumor chromatins allow distinguishing antigens of three main types: 1--antigens of nuclease-sensitive samples common both for normal and tumor cells; 2--antigens determined in tumor preparations only; 3--antigens usual for normal samples. Such differences in composition of immunogenic proteins in the nuclease-sensitive regions from the cells of the normal and malignant rat liver may be useful for investigating changes in active chromatin during chemical induction of tumors in animals.