FIG. 7.
Effects of cellular cyclin E (Cyc E) levels on growth suppression activities of p16 and p27. (A) Cyclin E protein levels in U2OS cells and a derivative cyclin E-transfected cell line (UE13) were determined by Western blotting of the total cell extracts with an anti-cyclin E antibody (HE12). (B) Growth suppression activities of p16 and p27 on U2OS and the cyclin E-transfected cell line were determined by transient transfection with pCMVp16 or pCMVp27 together with the transfection marker CD20. Empty vector was used as a baseline control. Transfected cells were analyzed by flow cytometry, and the cell cycle profiles of CD20-positive cells were determined. Differences in G1 percentage cells (Δ G1 %) between vector-transfected cells and cells transfected with p16 or p27 are presented.