Gene expression changes after TSA treatment and functional annotation of affected genes. (a) Hierarchical cluster analysis of the TSA-induced transcriptome. The numbers 1, 2, and 3 at the top represent three biological replicates of the experiment. Brackets on the left mark the two major clusters of down-regulates (cluster 1) and up-regulated (cluster 2) genes. Brackets on the right mark the subclusters of the four different expression profiles observed, that is, down-regulation after 12 h of TSA treatment (subcluster 1a) or after 6 h (subcluster 1b), and up-regulation after 6 h (subcluster 2a) or 12 h (subcluster 2b). (b) Pie charts representing the functional annotation of up- or down-regulated genes. Transcripts differentially expressed by ≥ 4-fold after 6 or 12 h of TSA treatment were used for all the above experiments.