(A) Cells were transfected with either a siRNA targeting Jab1 or a scrambled sequence (control); 48 hours later, the total cellular proteins and nuclear proteins were isolated and immunoblotted with anti-Jab1 and anti-p27 antibodies. Anti-β-actin or Lamin A/C antibodies were used as loading controls. (B) NPC cells were transfected as described in (A); 48 hours later, cells were stained with PI and then analyzed by flow cytometry. (Left) Representative results of cell cycle assays with NPC cells. (Right) The percentage of G1 and S phase cells are shown data represent three independent experiments, mean±s.d. * P <0.05, * *P <0.01. (C) Cells were transfected with either a siRNA targeting Jab1 or a scrambled sequence (control); 48 hours later, cell lysates were immunoprecipitated with Cdk2 and immunoblotted with anti-p27.