Abstract
The radioadaptive response is a defensive response where exposure to low dose radiation (priming dose) induces resistance against the subsequent high dose radiation (challenge dose). In order to identify the genes related to a radioadaptive response, we performed a DNA microarray analysis using the human lymphoblastoid-derived cell line AHH-1. The cells were unirradiated or irradiated with 0.02 Gy of priming dose, and the RNA was isolated 6 h after irradiation. In addition, cells unirradiated or irradiated with 0.02 Gy of priming dose were further irradiated with 3 Gy of challenge dose 6 h after priming irradiation, and the RNA was isolated 3 h after challenge irradiation. The gene expressions in cells irradiated with 0.02 Gy alone were compared with those in control cells using Student's t-test with the GeneSpring software, thereby 88 genes were selected as significantly modulated genes (p < 0.05). By a clustering analysis, it was revealed that the genes contained in a branch were significantly overlapped with a GO category 'Centrosome'. Similarly gene expressions in the cells irradiated with 3 Gy alone was compared with those in cells irradiated with 0.02 Gy plus 3 Gy. By a clustering analysis of 86 of significantly modulated genes, GO categories 'Metal ion binding', 'Zinc ion binding', 'Purine ribonucleoside salvage', 'Adenosine kinase activity', 'Ribonucleoside monophosphate biosynthetic process', 'Protein amino acid dephosphorylation' and 'Mitochondrion' were shown to be significantly overlapped with clusters of modulated genes. These GO categories are suggested to be the cellular functions related to the radioadaptive response of the AHH-1 cells.
