CYCLE DELAY IN IRRADIATED CYTOCHALASIN-INDUCED POLYKARYONS - DOES CYTOSKELETON STATUS AFFECT CELL-CYCLE CHECKPOINTS

Following exposure of CHO-KI cells to Cs-137 irradiation at doses up t o 20Gy, a delay in G(2) was observed to occur in cells permitted to di vide normally, while cells induced to become giants by means of cytoch alasin B demonstrated a minimal delay in the transition 2C - 8C sugges ting that the inhibition of cytokinesis results in modification of one or more cell cycle checkpoints. We postulate that this may occur as a consequence of damage tolerance, or by a feedback loop resulting from the reorganisation of the cytoskeleton that precludes cytokinesis.