DNA topoisomerase II is required at the time of mitosis in yeast

摘要: We have constructed five new temperature-sensitive DNA topoisomerase II mutations and analyzed their physiological consequences in yeast. Several lines of evidence suggest that the activity is required specifically at time miosis. First, top2 cause dramatic lethality restrictive temperature, but only if mutant cells are actively traversing cell cycle. Second, temperature-shift experiments with synchronized cultures show onset inviability coincides mitosis. Third, fluorescence microscopy reveals normal progression mitosis disturbed temperature. Finally, temperature prevented by nocodazole, an inhibitor tubulin polymerization prevents formation mitotic spindle. These results consistent hypothesis essential function to allow separation intertwined chromosomal molecules during