A cyclin B1 allele lacking CRM1-binding sites induces apoptosis.

(A) Transient transfection of NIH3T3 cells with cyclinB1Δ151 (myc epitope tagged) causes apoptosis, as measured by annexin staining, whereas transfection with the parental pCDNA3-myc vector does not. The figure is representative of 3 experiments. (B) Cells transfected with cyclinB1Δ151 express the protein predominantly in the nucleus as visualized by anti-myc antibody staining. Original magnification × 1000.