Topoisomerase 2 is dispensable for the replication and segregation of small yeast artificial chromosomes (YACs)

PLoS One. 2014 Aug 12;9(8):e104995. doi: 10.1371/journal.pone.0104995. eCollection 2014.

Abstract

DNA topoisomerases are thought to play a critical role in transcription, replication and recombination as well as in the condensation and segregation of sister duplexes during cell division. Here, we used high-resolution two-dimensional agarose gel electrophoresis to study the replication intermediates and final products of small circular and linear minichromosomes of Saccharomyces cerevisiae in the presence and absence of DNA topoisomerase 2. The results obtained confirmed that whereas for circular minichromosomes, catenated sister duplexes accumulated in the absence of topoisomerase 2, linear YACs were able to replicate and segregate regardless of this topoisomerase. The patterns of replication intermediates for circular and linear YACs displayed significant differences suggesting that DNA supercoiling might play a key role in the modulation of replication fork progression. Altogether, this data supports the notion that for linear chromosomes the torsional tension generated by transcription and replication dissipates freely throughout the telomeres.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromosome Segregation / genetics*
  • Chromosome Segregation / physiology*
  • Chromosomes, Artificial, Yeast / genetics*
  • Chromosomes, Artificial, Yeast / physiology
  • DNA Replication / genetics*
  • DNA Replication / physiology*
  • DNA Topoisomerases, Type II / metabolism*
  • DNA, Circular / genetics
  • DNA, Circular / metabolism
  • DNA, Fungal / genetics
  • DNA, Fungal / metabolism
  • DNA, Superhelical / genetics
  • DNA, Superhelical / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / physiology
  • Saccharomyces cerevisiae Proteins / metabolism
  • Telomere / metabolism

Substances

  • DNA, Circular
  • DNA, Fungal
  • DNA, Superhelical
  • Saccharomyces cerevisiae Proteins
  • DNA Topoisomerases, Type II

Grants and funding

This work was sustained by grant BFU2011-22489 to JBS from the Spanish Ministerio de Economía y Competitividad. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.