The study on genomic instability initiated by radiation signature using the chromosome transfer techniue

点击翻译按钮获取中文摘要

To know the mechanism for genomic instability induced by ionizing radiation, we studied chromosome instability induced by indirect action of radiation using microcell-mediated chromosome transfer. Mouse A9 cells containing a human chromosome 4 or 11 were irradiated with X-rays (4,6,15 Gy), and the irradiated human chromosome was transferred into unirradiated mouse m5S cells by microcell fusion. The stability of the transferred human chromosome was examined by fluorescent in situ hybridization (FISH). The results indicated that the irradiated chromosome per se was unstable compared to the unirradiated chromosome in some microcell hybrids. In addition, an unirradiated human was transferred into 4 Gy-irradiated mouse m5S cells by microcell fusion. The results showed that the unirradiated human chromosome was unstable, interacting with the irradiated mouse chromosomes in some microcell hybrids. These results suggest that an irradiated chromosome has unstable nature that is transmissible over many cell divisions. Moreover, chromosome analysis using telomere FISH indicated that telomere fusions mediated by telomere dysfunction was involved in the instability of the irradiated chromosome. Therefore, the present study indicates the significance of indirect action of radiation in the induction of chromosome instability.