FIG. 4.

Inhibition of cyclin D1 expression by PC3 in NIH 3T3 and Rb^−/− cells. NIH 3T3 and Rb^−/− 3T3 cells (3 × 10⁵) were seeded onto 90-mm-diameter culture dishes. After 24 h, cells were transfected with either pSCT empty plasmid (VEC; 21 μg for each dish, total of seven dishes for each cell line) or pSCT-PC3 (21 μg for each dish, total of seven dishes for each cell line), together with a plasmid encoding the CD20 cell surface marker (pCMVCD20, 3 μg). Sixty hours after, extracts from transfected cells isolated by CD20-specific cell sorting were subjected to immunoblotting with antibodies specific for the cyclin and CDK proteins indicated.