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Transcription Start under the Stress of Supercoiling and Template DNA Structure

Research Project

Project/Area Number 63460237
Research Category

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

Allocation TypeSingle-year Grants
Research Field 生物物性学
Research InstitutionKobe University

Principal Investigator

TACHIBANA Hideki  Kobe Univ., Faculty of Science, Assoc. Prof., 理学部, 助教授 (70126118)

Project Period (FY) 1988 – 1989
Project Status Completed (Fiscal Year 1989)
Budget Amount *help
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1989: ¥2,100,000 (Direct Cost: ¥2,100,000)
KeywordsDNA / Supercoil / Promoter / Transcription / プロモーター
Research Abstract

In the transcription start reaction of prokaryotes RNA polymerase is known to recognize the so-called -35 and -10 consensus sequences. Molecular mechanisms which determine the strength of each promoter as well as its change produced by supercoiling have not yet fully understood. In this research project, we first measured in vitro transcription activity of Escherichia coli lac promoter and its mutant promoter at various values of superhelical density ranging from 0 to -0.09. It was found that the increase in transcription activity with the increase in the negative superhelical density was larger for such promoters which were weak than those which were strong when supercoil was absent. Also, a new transcript which presumably started upstream of an authentic transcript appeared for the weak promoters when negative supercoil was introduced.
Further, when a cytosine-guanine alternating sequence, (CG)n, was inserted at -59 Position, the appearance of the above-mentioned novel transcript in r … More esponse to supercoil became reversed: it was observed at low negative supercoil and disappeared at high negative supercoil densities.
As a first step toward understanding the mechanisms which produces these effects of supercoiling on transcription in terms of three-dimensional structure of DNA, we employed a program by which a DNA helix trajectory can be calculated and applied it to ten or more promoters. It was shown that for most promoters the DNA helix axis was bent in the region between the -35 and the +1 sites, and the direction of bending was to the minus of the y-axis when we place the +1 base pair at the origin, the -35 region in the plus direction along the z-axis, and the x- and y-axes according to Dickerson's recommendation. This observation is very interesting in connection with the suggestion that the stress produced in the -35 to -10 region by binding of RNA polymerase induces DNA melting in the downstream region. It is necessary to further investigate the relation between the degree as well as detailed orientation of the bending and the strength as well as the response to supercoiling of promoters. This work was carried out in cooperation with Drs. R.D.Wells and Y.Nishimura. Less

Report

(3 results)
  • 1989 Annual Research Report   Final Research Report Summary
  • 1988 Annual Research Report
  • Research Products

    (9 results)

All Other

All Publications (9 results)

  • [Publications] H.Tachibana: "A novel transcription start under the stress of super coiling" (発表予定).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] H.Tachibana: "Unidirectional bending of promoter DNA in -35 to +1 rigion" (発表予定).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] H.Tachibana: "An'imtiator-terminator vector'suitable for direct expression of genic segmenst in Esherichiacoli" Protein Eng.(印刷中). (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] H. Tachibana & R.D.Wells: "A novel transcription start under the stress of supercoiling" (in preparation).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] H. Tachibana & Y. Nishimura: "Unidirectional bending of promoter DNA in -35 to +1 region" (in preparation).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] H. Tachibana, Y. Sasaki, H. Sawano & M. Kitakawa: "An 'initiator-terminator vector' suitable for direct expression of genic segments in Escherichia coli" Protein Eng.(1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] H.Tachibana: "A novel transcription start under the stress of supercoiling"

    • Related Report
      1989 Annual Research Report
  • [Publications] H.Tachibana: "Unidirectional bending of promoter DNA in -35 to +1 region"

    • Related Report
      1989 Annual Research Report
  • [Publications] H.Tachibana: "An ‘initiator-terminator vector' suitable for direct expression of genic segments in Escherichia coli" Protein Eng.(1990)

    • Related Report
      1989 Annual Research Report

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Published: 1989-04-01   Modified: 2016-04-21  

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