RT Journal Article T1 Changes in the topology of DNA replication intermediates: Important discrepancies between in vitro and in vivo A1 Schvartzman, Jorge Bernardo A1 Martínez, Víctor A1 Hernández, Pablo A1 Krimer, Dora A1 Fernández de Nestosa, María José A2 Universidad Nacional de Asunción - Facultad Politécnica AB The topology of DNA duplexes changes during replication and also after deproteinization in vitro. Here we describe these changes and then discuss for the first time how the distribution of superhelical stress affects the DNA topology of replication intermediates, taking into account the progression of replication forks. The high processivity of Topo IV to relax the left-handed (+) supercoiling that transiently accumulates ahead of the forks is not essential, since DNA gyrase and swiveling of the forks cooperate with Topo IV to accomplish this task in vivo. We conclude that despite Topo IV has a lower processivity to unlink the right-handed (+) crossings of pre-catenanes and fully replicated catenanes, this is indeed its main role in vivo. This would explain why in the absence of Topo IV replication goes-on, but fully replicated sister duplexes remainheavily catenated. YR 2021 FD 2021 LK http://hdl.handle.net/20.500.14066/3833 UL http://hdl.handle.net/20.500.14066/3833 LA eng NO CONACYT – Consejo Nacional de Ciencia y Tecnología DS MINDS@UW RD 29-abr-2024