Abstract
A derivative of murine immortal NIH/PG13Luc cells stably transfected with p53-dependent luciferase reporter plasmid was used for detection of transcriptional activity of p53 in response to radiation. We have identified several p53-dependent genes by microaray analysis expressed specifically in the cells after high dose rate or low dose rate irradiation. In the present analysis, we identified up-regulated genes specific to low dose rate irradiation (1, 10, 50, 100 mGy/h), but not to high dose rate irradiations (500 mGy/min), and then we performed quantification analysis of gene expression by using real time PCR method. The genes detected by microarray analysis, procollagen type I alpha 2, procollagen type V alpha 1, procollagen type V alpha 2, fibulin 5, tenascin C which are related to extracellular matrix. The expression levels of these genes showed the same tendency as those in real time PCR methods. And these genes expressed in a different manner from those in p53 responsive genes (cyclin G1, MDM2, p21). These data suggested that the low dose rate irradiations (1, 10, 50, 100 mGy/h) could be induced both cellular responses regulated by p53 dependent-transcription factors and other transcriptional factors. (This work was supported by Aomori Prefecture, Japan.)
