Abstract
It has been reported that a neutron has more influence on lives compared with an X-ray and a gamma ray. Although there are several reports concerning biological effects of neutrons, overall effects have not been clear yet. Here, we studied the molecular response to a thermal neutron in yeast cells by studying global gene expression-profiles (yeast cDNA microarray) using the Kyoto University Research Reactor. The yeast cells cultured in YPD medium were centrifuged, and resuspended with DW in plastic cuvets. Then, yeast cells were irradiated by 2.5Gy neutrons (containing 5.5Gy gamma ray) and 3.4Gy neutrons (containing 8.6Gy gamma ray). mRNA was extracted from these samples and used for the analysis of yeast cDNA microarray. The surviving ratios of treated cells were 79.7% (2.5Gy) and 74.45% (3.4Gy). Total numbers of induced genes (Cy5/Cy3 is more than 1.5) by neutrons were 62 genes (2.5Gy) and 247 genes (3.4Gy). Under treatments with 2.5 Gy neutrons, the number of Ty elements was more induced than that of stress-response genes and DNA repair genes. On the contrary, under treatments with 3.4Gy neutrons, many stress-response genes and DNA repair genes were induced though few Ty elements were induced. These results suggest that yeast cells have differential response depending on the dose of a neutron.
