Premitotic chromosome individualization in mammalian cells depends on topoisomerase II activity
Premitotic chromosome individualization in mammalian cells depends on topoisomerase II activity
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DOI：
10.1007/s004120000065
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发表时间：
2000-07-01
期刊：
影响因子：
1.6
通讯作者：
Downes, CS
中科院分区：
文献类型：
--
作者：
Giménez-Abián, JF;Clarke, DJ;Downes, CS
When DNA topoisomerase II (topo II) activity is inhibited with a non-DNA-damaging topo TI inhibitor (ICRF-193), mammalian cells become checkpoint arrested in G2-phase. In this study, we analyzed chromosome structure ill cells that bypassed this checkpoint. We observed a novel type of chromosome aberration, which we call R-figures. These are entangled chromosome regions that indicate the persistence of catenations between nonhomologous sequences. The number of Omega-figures per cell increased sharply as cells evaded the transient block imposed by the topo II-dependent checkpoint, and the presence of caffeine (a checkpoint-evading agent) potentiated this increase. Thus, the removal of nonreplicative catenations, a process that promotes chromosome individualization in G2, may be monitored by the topo II-dependent checkpoint in mammals.
