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1993 Fiscal Year Final Research Report Summary

A study of the topological change of DNA in Escherichia coli induced by heat shock.

Research Project

Project/Area Number 04680153
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 物質生物化学
Research InstitutionKYUSHU UNIVERSITY

Principal Investigator

SEKIMIZU Kazuhisa  Kyushu University, Department of Microbiology, Professor, 薬学部, 教授 (90126095)

Project Period (FY) 1992 – 1993
KeywordsDNA topology / DNA supercoiling / DNA topoisomerase / DNA gyrase / heat shock response / heat shock proteins / recombination / Escherichia coli
Research Abstract

Heat treatment of wild-type Escherichia coli cells leads to relaxation of negatively supercolied plasmid DNA, followed by a re-supercoiling reaction to the original level of the linking number of DNA.There was no evidence of the recovery of the DNA torsional strain in DNA of gyrA mutant cells. After heat treatment, DnaK and GroEL proteins were synthesized continuously in gyrA mutant cells but only transiently in wild-type cells. Thus, change in superhelical density of the DNA correlates with temperature -induced expression of heat shock proteins.
Inhibitors of DNA gyrase (nalidixic acid, novobiocin), an organic solvent (ethanol) and a psychotropic drug (chlorpromazine) all stimulated relaxation of cellular DNA, over the same concentration range that induced DnaK and GroEL proteins, As DNA relaxation was induced by heat treatment or chemicals in an rpoH, mutant, the process is not the result of any induced synthesis of heat shock proteins.
In rpoH and dnaK mutants, a re-supercoiling reaction did not occur, hence DnaK protein and other heat shock proteins presumably participate in the reaction. We propose that DNA relaxation induced by heat treatment stimulates synthesis of heat shock proteins involved in the re-supercoiling of DNA, which in turn shuts off the induction of these proteins.

  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] T.Mizushima,S.Natori and K.Sekimizu.: "Relaxation of supercoiled DNA associated with induction of heat shock proteins in Escherichia coli." Mol.Gen.Genet.238. 1-5 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Haq,S.Natori and K.Sekimizu.: "Heat-induced DNA relaxation in vitro by mouse DNA topoisomerase I in" J.Biochem.113. 620-624 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y.Ogata,T.Miki and K.Sekimizu.: "A role of heat shock proteins for homologous recombination in Escherichia coli." Biochem.Biophys.Res.Commun.197. 34-39 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y.Ogata,T.Mizushima,K.Kataoka,T.Miki and K.Sekimizu.: "Identification of DNA topoisomerases in volved in immediate and transient DNA relaxation induced by heat shock in Escherichia coli." Mol.Gen.Genet.(印刷中). (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Mizushima, S.Natori and K.Sekimizu: "Relaxation of supercoiled DNA associated with induction of heat shock proteins in Escherichia coli." Mol.Gen .Genet.238. 1-5 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.Hag, S.Natori and K.Sekimuzu: "Heat-induced DNA relaxation in vitro by mouse DNA topoisomerase I in the presence of ethidium bromide." J.Biochem.113. 620-624 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Ogata, T.Miki and K.Sekimizu: "A role of heat shock proteins for homologous recombination in Escherichia coli." Biochem.Biophys.Res.Commun.197. 34-39 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Ogata, T.Mizushima, K.Kataoka, T.Miki and K.Sekimizu: "Identification of DNA topoisomerases involved in immediate and transient DNA relaxation induced by heat shock in Escherichia coli." Mol.Gen.Genet. in press. (1994)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1995-03-27  

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