Hierarchical clustering of stress response gene expression data. The clustering includes 4145 genes (rows) under 12 different stress conditions (columns). Colors indicate gene expression log ratios compared to relevant controls; (yellow) up-regulation; (blue) down-regulation. The 20-min nitrogen starvation data are from the present investigation and the other data are from Mata et al. (2002) and Chen et al. (2003). At left, CESR-induced genes are labeled in blue, and CESR-repressed genes in orange.