Kinetics of Nuclease Digestion of Physarum polycephalum Nuclei at Different Stages of the Cell Cycle

Abstract

The kinetics of digestion of P. polycephalum nuclei by staphylococcal nuclease and DNase I was studied at different stages of the cell cycle. Significant differences in the digestion behavior of nuclei from metaphase and interphase were detected with DNase I but not with staphylococcal nuclease. Furthermore the structure of newly replicated DNA in S phase differs from the bulk in that it is more easily degraded to acid-soluble products by either staphylococcal nuclease or by DNase I. At least 4 types of chromatin structure can be distinguished by the digestion kinetics experiments.