AbstractThis is a review paper to introduce our recent studies on the genetic effects of low-dose and low-dose-rate ionizing radiation (IR). Human lymphoblastoid TK6 cells were exposed to γ-rays at a dose-rate of 1.2mGy/h (total 30mGy). The frequency of early mutations (EMs) in the thymidine kinase (TK) gene locus was determined to be 1.7×10−6, or 1.9-fold higher than the level seen in unirradated controls [Umebayashi, Y., Honma, M., Suzuki, M., Suzuki, H., Shimazu, T., Ishioka, N., Iwaki, M., Yatagai, F., Mutation induction in cultured human cells after low-dose and low-dose-rate γ-ray irradiation: detection by LOH analysis. J. Radiat. Res., 48, 7–11, 2007]. These mutants were then analyzed for loss of heterozygosity (LOH) events. Small interstitial-deletion events were restricted to the TK gene locus and were not observed in EMs in unirradated controls, but they comprised about half of the EMs (8/15) after IR exposure. Because of the low level of exposure to IR, this specific type of event cannot be considered to be the direct result of an IR-induced DNA double strand break (DSB).To better understand the effects of low-level IR exposure, the repair efficiency of site-specific chromosomal DSBs was also examined. The pre γ-irradiation under the same condition did not largely influence the efficiency of DSB repair via end-joining, but enhanced such efficiency via homologous recombination to an about 40% higher level (unpublished data). All these results suggest that DNA repair and mutagenesis can be indirectly influenced by low-dose/dose-rate IR.


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    Titel :

    Influence of low-dose and low-dose-rate ionizing radiation on mutation induction in human cells


    Beteiligte:
    Yatagai, F. (Autor:in) / Umebayashi, Y. (Autor:in) / Suzuki, M. (Autor:in) / Abe, T. (Autor:in) / Suzuki, H. (Autor:in) / Shimazu, T. (Autor:in) / Ishioka, N. (Autor:in) / Iwaki, M. (Autor:in) / Honma, M. (Autor:in)

    Erschienen in:

    Advances in Space Research ; 40 , 4 ; 470-473


    Erscheinungsdatum :

    2007-04-03


    Format / Umfang :

    4 pages




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch