Figure 2.

Heatmap of transcriptome profiling data illustrating co-expressed sets of genes associated with various toxicants, such as genotoxic agents (red side bars). Some agents also exhibit obvious pleiotropy; e.g., chromate induced expression of genes associated with genotoxic agents (red side bars) and genes associated with cadmium and heat shock (blue side bars). This heatmap contains 1,628 genes that were significantly (P < 0.01; t-test) perturbed at least 1.7-fold, relative to the control, by at least one stress agent. The genes in the heatmap were organized by hierarchical clustering with complete linkage based on their error-weighted Pearson distances. The genotoxic (red side bars) and cadmium and heat shock (blue side bars) signatures were identified using coupled two-way clustering. The arrow highlights a cluster of genes responding to ER stress agents thapsigargin and tunicamycin as well as certain other agents.