HEY peaks are clustered at transcription start sites of active promoters with a preference for developmental and transcriptional regulatory genes.

<p>(A) Histograms show the number of HEY1 and HEY2 peaks within a certain distance to the closest transcription start site (TSS) of the human hg19 refseq genome. Quartiles indicate the window around the median distance containing 50% of all peaks. (B) Pie charts identify main peak locations within genes. (C) K-means clustered heat maps of ChIPseq signals in HEK293 cells for HEY1, HEY2, uninduced control, RNA polymerase II (PolII) and histone-3-lysine-4-trimethylation (H3K4me3). Graph includes all hg19 refseq TSS (+/−1 kb). (D) GO term analysis identifies enriched biological processes among genes with high HEY1 and HEY2 peaks (top 1000 peaks according to height). The top annotation clusters are shown according to their cluster enrichment score [−lg(mean p-value)]. Cluster names are based on enriched GO annotations.