Fig. 3. 14-3-3 binding mutant of Wee1 is impaired in its ability to induce a G2 cell cycle delay. HeLa cells synchronized by a double thymidine block protocol were infected with recombinant adenoviruses encoding either GFP (A) or with viruses encoding myc-epitope tagged wild-type Wee1 (B) or a mutant of Wee1 containing alanine in place of serine at position 642 (Wee1S642A; C). Cells were harvested at various times (hours) after release from the block, and cellular DNA content was analyzed by flow cytometry. Levels of Wee1 and Wee1(S642A) were determined by immunoblotting (D).