E2F4’s target gene signature consists of 199 genes and reflects its activity in the cell cycle. (A) A Venn diagram of target genes identified by ChIP-seq experiments in the HeLa, K562, and GM06900 cell lines. Using a P value <0.01 threshold, 199 genes are found to be targeted by E2F4 across all three cell lines. (B) E2F4 activity and expression levels throughout the cell cycle in HeLa S3 cells. Activity is calculated as the regulatory activity score (RAS) and expression is calculated in log ratio from cDNA array. The inferred E2F4 activity derived from RAS (solid black line), but not the E2F4 expression level (hashed gray line), is significantly periodic during the cell cycle. ChIP-seq, chromatin immunoprecipitation sequencing.