Identification of DNA topoisomerases involved in immediate and transient DNA relaxation induced by heat shock in Escherichia coli

Yasuyuki Ogata, Tohru Mizushima, Kazuhiro Kataoka, Takeyoshi Miki, Kazuhisa Sekimizu

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

The linking number of plasmid DNA in exponentially growing Escherichia coli increases immediately and transiently after heat shock. The purpose of this study was to search for DNA topoisomerases that catalyze this relaxation of DNA. Neither introduction of a topA deletion mutation nor treatment of cells with DNA gyrase inhibitors affected the DNA relaxation induced by heat shock. Thus, DNA topoisomerase I and DNA gyrase are apparently not involved in the process. However, the reaction was inhibited by nalidixic acid or by oxolinic acid in the topA mutant and the reaction was resistant to nalidixic acid in a topA mutant carrying, in addition, the nalA26 mutation. These results are interpreted as indicating that both DNA topoisomerase I and DNA gyrase are involved in the DNA relaxation induced by heat shock.

Original languageEnglish
Pages (from-to)451-455
Number of pages5
JournalMGG Molecular & General Genetics
Volume244
Issue number5
DOIs
Publication statusPublished - 1994 Sep 1

Keywords

  • DNA gyrase
  • DNA relaxation
  • DNA topoisomerase I
  • Heat shock
  • topA

ASJC Scopus subject areas

  • Genetics

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