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Role of the initiator titration mechanism in the initiation of chromosomal replication

Research Project

Project/Area Number 13680761
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Molecular biology
Research InstitutionNagoya University

Principal Investigator

OGAWA Tohru  Nagoya University, Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (80109256)

Project Period (FY) 2001 – 2002
Project Status Completed (Fiscal Year 2002)
Budget Amount *help
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2002: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2001: ¥1,600,000 (Direct Cost: ¥1,600,000)
KeywordsDNA replication / DnaA / oriC / initiation of replication / datA / IHF
Research Abstract

Replication of the Escherichia coli chromosome is initiated at a unique site, oriC. Concurrent initiations occur at all oriC sites present in a cell once and only once at a fixed time in the cell cycle. A mechanism to ensure the cyclic initiation events operates through the chromosomal site, datA, which titrates exceptionally large amounts of the bacterial initiator protein, DnaA, A strain lacking datA grew normally but exhibited the asynchronous initiation phenotype due to extra initiation events. The DnaA titration mechanism to control replication initiation appears to be, intrinsic to datA, inasmuch as deletion of other DnaA-binding sites (DnaA boxes) on the chromosome does not provoke such aberrant initiations.
In the present study, efforts were made to clarify the unique mechanism of DnaA titration by datA. Analyses of phenotypes of strains carrying mutations at various sites in datA revealed that, of the five DnaA boxes in datA, both the second and the third boxes are essential for the initiation control. A consensus sequence of binding of the integration host factor (IHF) is present between the two DnaA boxes. We have proven that IHF protein really binds to this site. Furthermore, the IHF binding greatly enhanced the amounts of DnaA molecules titrated to datA. Binding of IHF to its recognition site has been known to cause DNA bending of about 160 degree. This bending should bring the second and the third DnaA boxes to close proximity and enable bridging the DNA strands by DnaA-DnaA interaction bound to the two DnaA boxes, leading to the formation of a large DnaA titration pool.
Destruction of the IHF-binding site in datA on the chromosome caused overinitiation phenotype similar to that observed with the datA-deleted strain, demonstrating the involvement of IHF in DnaA titration to datA in vivo.

Report

(3 results)
  • 2002 Annual Research Report   Final Research Report Summary
  • 2001 Annual Research Report
  • Research Products

    (9 results)

All Other

All Publications (9 results)

  • [Publications] Tohru Ogawa: "The datA locus predominantly contribute to the initiator titration mechanism in the control of replication initiation in Escherichia coli"Mol.Microbiol. 44・5. 1367-1375 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Toru Ozaki: "Anomalous DnaA protein binding to the regulatory region of the Escherichia coli aldA gene"Microbiology. 147. 153-159 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Tsutomu Katayama: "Multiple pathways regulating DnaA function in Escherichia coli : Distinct rolesfor DnaA titration by datA locus and the regulatory inactivation of DnaA"Biochimie. 83. 13-17 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Ogawa,T., Yamada,Y., Kuroda,T.and Moriya,S.: "The datA locus predominantly contribute to the initiator titration mechanism in the control of replication initiation in Escherichia coli"Mol.Microbiol.. 44. 1367-1375 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Ozaki,T., Kumaki,Y., Kitagawa,R.and Ogawa,T.: "Anomalous DnaA protein binding to the regulatory region of the Escherichia coli aldA gene"Microbiology. 147. 153-159 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Katayama,T., Fujimitsu,K.and Ogawa,T.: "Multiple pathways regulating DnaA function in Escherichia coli : Distinct roles for DnaA titration by the datA locus and the regulatory inactivation of DnaA"Biochimie. 83. 13-17 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Tohru Ogawa: "The datA locus predominantly contribute to the initiator titration mechanism in the control of replication initiation in Escherichia coli"Mol. Microbiol.. 44(5). 1367-1375 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] Toru Ozaki: "Anomalous DnaA protein binding to the regulatory region of the Escherichia colialdA gene"Microbiology. 83. 153-159 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] Tsutomu Katayama: "Multiple pathways regulating DnaA function in Escherichia coli: Distinct rolesfor DnaA titration by datA locus and the regulatory inactivation of DnaA"Biochimie. 83. 13-17 (2001)

    • Related Report
      2001 Annual Research Report

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Published: 2001-04-01   Modified: 2016-04-21  

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