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2000 Fiscal Year Final Research Report Summary

Involvement of telonomic instability in induction of delayed chromosome aberrations by ionizing radiation

Research Project

Project/Area Number 11680552
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 環境影響評価(含放射線生物学)
Research InstitutionNagasaki University

Principal Investigator

KODAMA Seiji  Nagasaki University, School of Pharmaceutical Sciences, Associate Professor, 薬学部, 助教授 (00195744)

Co-Investigator(Kenkyū-buntansha) SUZUKI Keiji  Nagasaki University, School of Pharmaceutical Sciences, Research Associate, 薬学部, 助手 (00196809)
WATANABE Masami  Nagasaki University, School of Pharmaceutical Sciences, Professor, 薬学部, 教授 (20111768)
Project Period (FY) 1999 – 2000
Keywordsradiation / delayed chromosome aberration / genetic instability / oxidative stress / scid mouse / telomere / telonomic instability / FBB cycle
Research Abstract

Ionizing radiation induces genetic instability in the progeny of irradiated cells. To elucidate the role of oxidative stress in the susceptibility to induction of genetic instability by ionizing radiation (IR), we examined X-ray-induced delayed chromosome aberrations in human embryo cells under normally oxygenated (20%) and hypoxic (2%) conditions. The results revealed that hypoxia reduced the delayed chromosome aberrations, suggesting that oxidative stress plays a significant role in the induction of genetic instability by IR.To know the role of repair process for DNA double-strand breaks (DBSs) in the induction of genetic instability, we studied X-ray-induced delayed chromosome aberrations in scid mouse cells, which defect in non-homologous end-joining repair for DSBs. The chromosome analysis revealed that scid cells were 2-fold more susceptible to the induction of delayed dicentric chromosomes than wild-type cells even though they received an equivalent survival dose. This result suggests that the impaired repair for DSBs might contribute to the high susceptibility to the induction of genetic instability. To know the mechanism for the formation of delayed dicentric chromosomes, we examined telomere sequences remained at the junctional position of two chromosomes in the delayed dicentric chromosomes using telomere-FISH (t-FISH) technique. The result showed that X-irradiation enhanced the induction of telomeric fusions where the t- FISH positive signals remained at the junctional position and also that the higher percentage of telomeric fusions in scid cells than in wild-type cells. From these results, we propose that the induction of delayed chromosome aberrations is mediated by fusion-bridge-breakage (FBB) cycle possibly initiated with telonomic instability induced by IR.

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] Kanaklata Roy: "Delayed cell death, giant cell formation and chromosome instability induced by X-irradiation in human embryo cells"Journal of Radiation Research. 40. 311-322 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] J.C.Ghosh: "Dose-dependent biphasic accumulation of TP53 protein in normal human embryo cells after X irradiation"Radiation Research. 153. 305-311 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Kanaklata Roy: "Hypoxia relieves X-ray-induced delayed effects in normal human embryo cells"Radiation Research. 154. 659-666 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 漆原あゆみ: "放射線誘発遅延型染色体異常に対するscid突然変異の影響"長崎医学会雑誌. 75. 251-253 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Keiji Suzuki: "Radiation-induced senescence-like growth arrest requires TP53 function but not telomere shortening"Radiation Research. 155. 248-253 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Seiji Kodama: "Culture condition-dependent senescence-like growth arrest and immortalization in rodent embryo cells"Radiation Research. 155. 254-262 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Roy et al.: "Delayed cell death, giant cell formation and chromosome instability by X-irradiation in human embryo cells"J.Radiat.Res. 40. 311-322 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] J.C.Ghosh et al.: "Dose-dependent biphasic accumulation of TP53 protein in normal human embryo cells after X irradiation"Radiat.Res. 153. 305-311 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Roy et al.: "Hypoxia relieves X-ray-induced delayed effect in normal human embryo cells"Radiati.Res.. 154. 659-666 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A.Urushibara et al.: "Effect of scid mutation on induction of delayed chromosome aberrations by ionizing radiation (in Japanese)"Nagasaki Igakukai Zashi. 75. 251-253 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Suzuki et al.: "Radiation-induced senescence-like growth arrest requires TP53 function but not telomere shortening"Radiat.Res.. 155. 248-253 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.Kodama et al.: "Culture-condition-dependent senescence-like growth arrest and immortalization in Rodent embryo cells"Radiat.Res.. 155. 254-262 (2001)

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

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Published: 2002-03-26  

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