Abstract
Multinucleate condition was induced in Chinese hamster cells by treatments with bleomycin (BLM) and cytochalasin B (CB). BLM initially induced chromosome aberrations, such as breaks and reunions, and the resulting lagging chromosomes or acentric fragments formed micronuclei after cell division. CB inhibited cytokinesis, but not karyokinesis, which resulted multinucleate cells. In parallel with the appearance of the micronucleate or multinucleate interphase cells, there observed in metaphase cells “pulverized” or “prophased” chromatin (PC). Autoradiographic analyses revealed that nuclear asynchronization and subsequent asynchronous mitosis were prerequisite for the induction of PC in the interphase nuclei. Several characteristic morphologic features of PC were distinguishable depending on the different cell cycle of the affected interphase chromatin, i. e., the different degree of asynchrony between the mitotic and interphase nuclei.
