Human and macaque MCPH1 can directly interact with E2F1 . (A) Interaction of the transfected E2F1 and MCPH1 in HEK293T cells. (B) Co-localization of MCPH1-GFP and RFP-E2F1 in HEK293T cells. White arrows indicate co-staining areas. (C) Expression of the HA-tagged human and macaque MCPH1s were verified by Western blot using anti-HA monoclonal antibody (top panel), and the HA-tagged E2F1 was also verified by Western blot (middle panel). The bottom panel is the actin control. (D) Quantification of E2F1 and MCPH1 transcriptional activity using the E2F4B constructs. All histograms represent the mean ± SD of at least nine data points, including both biological and technical replicates (* P <0.05,** P <0.01, *** P <0.001, n.s, not significant).