Figure 1

Validation of gene expression measurements. Heat-maps of log₂ transformed expression ratios in (A.) irradiated and (B.) bystander cells to time matched sham-irradiated controls across the time points in hours (H) using both microarray and quantitative real time PCR methods. On the scale bar, red indicates up-regulation and green, down-regulation of mRNA compared to controls. Two major clusters of genes are evident: the biphasic response group with two distinct up-regulation peaks synchronously activated in both conditions, and 4-hour peak response genes in irradiated cells with a muted response in bystanders. Data are medians across four independent biological replicates.