Figure 4
Temporal patterns of significantly changed genes in response to 56Fe, 28Si and γ-ray irradiations. A, The major temporal patterns of genes whose expression is associated with a particular radiation type are displayed. These patterns correspond to the first three components from principal component analysis (PCA). B, Genes associated with p53 signaling and/or involved in cell cycle regulation exhibited similar kinetics of expression in response to different radiation qualities. Average log2 ratios from three replicate experiments were used in the plot. Error bar: standard error. C, Using a single representative experiment, microarray expression values at a given time for the genes in Figure 4B were validated using qRT-PCR. The log2-ratios of irradiated vs. mock samples from both qRT-PCR and microarray analysis of the corresponding replicate were plotted. The up-regulation of these genes at the indicated time points was confirmed.