Fig. 7. VRK1 mediates Myc-induced CCND1 expression. (A) HeLa cells were cotransfected with pHA empty vector (Vector) or pHA-Myc and control siRNA (siCont) or siVRK1. Cells were immunoblotted with the indicated antibodies. (B) Immunofluorescence of Myc-EBFP (blue), VRK1 (green) and CCND1 (red) from cells transfected with siCont or siVRK1. Arrowheads and arrow denote untransfected cells and cells that do not show knockdown, respectively. Scale bars: 20 µm. (C) ChIP assay measuring Myc binding to conserved Myc-binding sites in the VRK1 promoter of HeLa cells transfected with pHA empty vector or pHA-Myc. (D) Cells were maintained without serum for 24 hours then fetal bovine serum was added to 5% and cells incubated for a further 3 hours. Cells were then immunostained for VRK1 (red), Myc (green) and DNA (Hoechst 33342, blue). DIC, digital interference contrast image. Scale bar: 30 µm.