How inhibition of EZH1/2 changes the transcriptional response to VPA. Human lymphoblastoid cells were treated for 2 hours with either 1mMVPA, 3 µM UNC1999 (an inhibitor of the methyltransferase activity of EZH1/2) or both compounds together. a Western blot showing changes in H3K27me3 levels in LCLs treated with 3 µM UNC1999 for the indicated times. b Venn diagrams comparing the response to VPA alone and VPA + UNC1999, and identifying genes that are UNC1999 sensitive, UNC1999-insenstive, or whose transcription changes only in the presence of UNC1999 (UNC1999-dependent), as indicated. For each treatment, gene expression changes were compared to untreated cells. Significant genes were determined by t test (fold change >1.5, P < 0.05). c Pre-treatment levels of H3K27ac and H3K27me3 at the TSS of genes whose transcription changes (up or down as specified) in response to VPA and/or UNC1999. Box plots show results for all TSS (All probes, LH side), and for genes responding to UNC1999 alone (UNC-responsive), VPA only in the absence of UNC1999 (UNC-sensitive), VPA with or without UNC1999 (UNC-insensitive) and VPA only in the presence of UNC1999 (UNC-dependent). Box plots are configured as in Fig. 4.