Cluster analysis and functional annotation of the differentially regulated genes of the time course of sorbitol treatment. (A) A non-redundant set of 809 genes that were up- or down-regulated more than 1.5 fold in the time course of sorbitol treatment was clustered with GeneSpring 7.2. Four major clusters (1–4) can be distinguished. The dendrogram is displayed on the left. The differentially regulated genes are depicted as coloured lines and the time of treatment in minutes is shown at the bottom. The colour represents the fold induction (red) or repression (blue) as shown in the colour scale below the figure. Non-regulated genes are displayed in yellow. (B) A selection of the GO biological process terms that were enriched in each of the clusters is presented. GO tree levels are shown on the left. Bar lengths represent the fold enrichment (scale x-axis). The table indicates the number of genes with a particular annotation in the cluster (List), on the entire array (Total), the significance for enrichment (P-value) and the annotation. (C) Expression profiles of selected genes from each cluster. The following abbreviations for differentially regulated genes are used. Cluster 1: rto A, Ratio A; psm B6, 20S proteasome subunit beta-6; psm C4, 26S proteasome subunit ATPase 4; psmD 11, 26S proteasome non-ATPase regulatory subunit 11; psmD 2, 26S proteasome regulatory subunit 2; cpi C, Cysteine Protease Inhibitor; cpr A, cysteine proteinase 1. Cluster 2: cor A, coronin; arp B, actin related protein 2; pro B, profilin II; nap A, NCK-Associated Protein; abp C, actin binding protein; act8, actin8. Cluster 3: dst C, Dictyostelium STATc; gap A, RasGTPase-activating protein; svk A, Severin kinase; abc G21, ABC transporter G family protein. Cluster 4: vat, vacuolar H+-ATPase subunit.