| Literature DB >> 10968252 |
J F Giménez-Abián1, D J Clarke, J Devlin, M I Giménez-Abián, C De la Torre, R T Johnson, A M Mullinger, C S Downes.
Abstract
When DNA topoisomerase II (topo II) activity is inhibited with a non-DNA-damaging topo II inhibitor (ICRF-193), mammalian cells become checkpoint arrested in G2-phase. In this study, we analyzed chromosome structure in cells that bypassed this checkpoint. We observed a novel type of chromosome aberration, which we call omega-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.Entities:
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Year: 2000 PMID： 10968252 DOI： 10.1007/s004120000065
Source DB: PubMed Journal: Chromosoma ISSN： 0009-5915 Impact factor: 4.316