Effect of polyamines and divalent cations on histone H1-poly(adenosine diphosphate ribose) complex formation

When the polyamines spermine, spermidine or putrescine at 1 or 2 mM were added to HeLa cell nuclei, there was a 1- to 3-fold differential stimulation of ³H]NAD incorporation into an H1 histone-poly(ADP-ribose) complex with little effect on total poly(ADP-ribose) synthesis. At higher polyamine levels, total polymer synthesis was inhibited, but the fraction of polymer associated with H1 was still differentially increased. A differential stimulation of complex synthesis was also produced by the addition of elevated levels of Mg²⁺ or Ca²⁺. These results were not due to an effect of these agents on recovery or turnover of the H1-poly(ADP-ribose) complex but apparently are related to the chromatin condensing action of these agents since enhanced formation of the H1-poly(ADP-ribose) complex and of chromatin aggregation was closely correlated.