Comparative aspects of nuclear proteins and nuclear composition of cultivated embryonic, neonatal and neoplastic rat brain cells of glial origin.

Differences in nuclear composition and variations in the types of acid soluble nuclear proteins were identified when cultivated neoplastic and nontransformed rat brain cells were compared. HeLa S-3 cells were used as a biological reference in these studies. The nuclei of anaplastic glioma cells were found to contain more total nuclear protein and greater amounts of nuclear RNA, than the nuclei of nontransformed embryonic and neonatal rat brain cells. Densitometer profiles of samples developed by polyacrylamide gel electrophoresis indicated that all three major histone classes were present in the nuclei of the four different cell types examined. Each type of cell was grown in the presence of 3H-lysine or 3H-lysine plus 14C-arginine to further characterize both the histones and the acid soluble nonhistone proteins. Neoplastic and nontransformed cells contained similar quantities of histones H4, H3, H2A and H2B. In contrast, transformed cells were found to contain two dominant subspecies of lysine rich H1 histone, while only one histone H1 subcomponent was extracted from the nuclei of the embryonic and neonatal rat brain cells. Nuclei isolated from HeLa cells and anaplastic glioma cells also contained increased varieties and larger quantities of acid soluble nonhistone nuclear proteins.