Regulation of gene expression during the time-course experiment in control and UVC-irradiated cells. The expression pattern of 133 genes whose expression changed significantly (P ≤ 0.05) during the time course are shown. The columns represent samples taken after 0, 30 or 90 min in control and UVC-irradiated cells. Hierarchical clustering was performed as described in Methods, pairing the 133 genes in the different samples according to their expression level. The changes in transcription level are colour coded with induced genes as green and repressed genes as blue.