Decatenation of daughter DNA Sample Clauses

Decatenation of daughter DNA. Intertwined duplex DNA can only be resolved (decatenated) by Topoisomerase II. Thus, catenated replication products are only resolved when it is present, despite the fact that replication proceeds normally in its absence (presumably due to the presence of Topoisomerase I) (Xxxxx et al. 2015; Xxxxxx and Xxxxxxx, 2008; XxXxxxx et al. 1984). This has also been demonstrated in a fully reconstituted replication system (Xxxxxxxxxxx et al. 2017). However, the inability to decatenate results in fatal problems downstream of replication for cells. In the complete absence of Topoisomerase II, for example, chromosomes are extensively missegregated in vivo; in the absence of catalytically active Topoisomerase II, cells arrest in G2 (Xxxxxx and Xxxxxxx, 2008). In either case, this leads to cell death (Xxxxxx and Xxxxxxx, 2008; XxXxxxx et al. 1984; Xxxx et al. 1985; Xxxxxx and Xxxxxxxx, 1984). It is not clear when decatenation occurs in the sequence of events that constitute the end of replication, although it is not required for fork convergence and ligation (Xxxxx et al. 2015). It is often depicted as occurring after replisome convergence and replisome disassembly (though it may occur simultaneously with these other processes).