[Cellular behavior and centriole distribution during multipolar mitosis induced by nocodazole action]

After recovery from the nocodazole blockade, mitoses in PE cells proceed differently depending on the time of treatment and on the drug concentration. Cells, treated with 0.02 mcg/ml for 3 hours or less, have a recovery period of 1-1.5 hours, however cells, treated with 0.02 mcg/ml for more than 3 hours or with 0.2 mcg/ml at a time, have a recovery period of 3-4 hours. In both the cases anaphase and cytokinesis proceed normally. The 0.6 mcg/ml nocodazole concentration results in the appearance of only multipolar mitoses during recovery. The minimal-time multipolarity induction is 1 hour. Cytokinesis is disturbed in 60% of multipolar mitoses: two of the three daughter cells are fused to form a binucleated cell. A complete disruption of the mitotic apparatus causes one of the diplosomes to dissociate. In the first minutes of recovery, the other diplosome dissociates too. In tripolar telophase centrioles distributed among the spindle poles according to the 2 : 2 : 0 pattern, as a rule. Thus, the deranging of the mitotic spindle is a necessary and sufficient condition for the induction of multipolar mitoses in tissue culture cells. This derangement accompanies the dissociation of diplosomes, but single daughter centrioles do not form a spindle pole.