Fig. 8. Expression of p21 in p21 and control-transfected cells. The mock-transfected K562 clone M1 was transfected with control vector or the cDNA for p21, respectively, as described in "Materials and Methods." After 72 h, the cells were subjected to Western blot. Arrow to the right, position of p21 protein at Mr 21,000. Left, positions of molecular weight standards.