From Genome to Life:

DUTREIX Marie

Institut Curie, UMR CNRS-IC 2027, Bat 110, Centre Universitaire, Orsay 91405, France

title: Cellular consequences of growth in continuous exposure to low doses of ionizing radiations: detection of epigenetic changes using DNA microarrays "

M. DUTREIX , G. MERCIER, Y. DENIS AND J. PEYRE

One of the major problems in public health is to estimate the effect on the organisms of continuous exposure to very low doses of genotoxics. The risk is often estimated from data calculated with an equivalent cumulative dose applied during a short period. In this work, we analyze the accuracy of such estimation by comparing the effects in Saccharomyces cerevisiae of an exposure to a given dose of ionizing radiations delivered in few minutes or continuously during 20 hours. The survival, the cell growth, the homologous recombination and the mutagenesis have been measured in both conditions and indicate that the effects induced by permanent exposure are cumulative. The analysis of the whole transcriptome, using DNA microarrays, indicates that cells from cultures continuously exposed to low doses of radiation, over-express 69 genes and under-express more than 155 genes. The interest and the limits of the microarrays technique will be discussed through this example