| Abstract: | Hybrid HeLa cells formed by the fusion of mitotic with interphase cells have been used as a test system to study the effects of various positively and negatively charged compounds on the induction of premature chromosome condensation (PCC) of the interphase nuclei. Among the various positively charged compounds tested, spermine, putrescine and Mg++ were specific in promoting the PCC induction while spermidine was unique in inhibiting this event. All the negatively charged compounds including estradiol-17β were uniformly inhibitory. The inhibitory effect of estradiol was reversed by putrescine. The inhibition of PCC induction by estradiol seems to be due to its binding to interphase chromatin rather than to the PCC inducers. The differences between the polyamines in their effects on the PCC inducing system has been explained on the basis of their abilities to bind stereospecifically with chromatin. |
