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Interplay of DNA supercoiling and catenation during the segregation of sister duplexes

By María Luisa Martínez-Robles, Guillaume Witz, Pablo Hernández, Jorge B. Schvartzman, Andrzej Stasiak and Dora B. Krimer

Abstract

The discrete regulation of supercoiling, catenation and knotting by DNA topoisomerases is well documented both in vivo and in vitro, but the interplay between them is still poorly understood. Here we studied DNA catenanes of bacterial plasmids arising as a result of DNA replication in Escherichia coli cells whose topoisomerase IV activity was inhibited. We combined high-resolution two-dimensional agarose gel electrophoresis with numerical simulations in order to better understand the relationship between the negative supercoiling of DNA generated by DNA gyrase and the DNA interlinking resulting from replication of circular DNA molecules. We showed that in those replication intermediates formed in vivo, catenation and negative supercoiling compete with each other. In interlinked molecules with high catenation numbers negative supercoiling is greatly limited. However, when interlinking decreases, as required for the segregation of newly replicated sister duplexes, their negative supercoiling increases. This observation indicates that negative supercoiling plays an active role during progressive decatenation of newly replicated DNA molecules in vivo

Topics: Structural Biology
Publisher: Oxford University Press
OAI identifier: oai:pubmedcentral.nih.gov:2731910
Provided by: PubMed Central

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Citations

  1. (2004). A topological view of the replicon.
  2. (1998). DNA gyrase and topoisomerase IV: Biochemical activities, physiological roles during chromosome replication, and drug sensitivities.
  3. (2005). DNA Topology.
  4. (2008). Independent positioning and action of Escherichia coli replisomes in live cells.
  5. (2008). Modulation of Escherichia coli sister chromosome cohesion by topoisomerase IV.
  6. (2001). Topoisomerase II can unlink replicating DNA by precatenane removal.

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