Flow cytometric methods for studying isolated nuclei: DNA accessibility to DNase I and protein-DNA content.

Two FCM methods utilizing isolated nuclei were described. A DNase I sensitivity assay, employing changes in binding and digestion kinetics of the enzyme as well as the binding of intercalating fluorochrome was used to observe structural changes of chromatin rendered by physical and chemical agents. A nuclear DNA-protein staining method was used to study changes in nuclear protein content, redistribution of populations in the cell cycle, and unbalanced growth, manifested as an extraordinary accumulation of nuclear protein brought about by physical and chemical perturbation.