Drug modulation of chromosomal protein subtypes during specific phases of the submaxillary cell cycle

The H 1 subtype proteins a, b, c, d, e, and 1 ∘ and the high mobility group (HMG) proteins 14 and 17 were extracted from submaxillary gland (SMG) nuclei treated in vivo and sorted from specific phases of the cell cycle, and analyzed by gel electrophoresis. Significant differences in these proteins were noted between quiescent (G 0) phase nuclei and proliferating nuclei in both stained and autoradiographic gels. Stimulation of the SMG into cell division with DL-isoproterenol-HCl alone or in conjunction with sodium phenobarbital (PB) provided a system, for the analysis of drug effects in stained, 3H lysine, and 32P pulse-labeled nuclear proteins obtained from different phases of the cell cycle.