Fig. 7.

(A) Uncoupling of securin and cyclin B degradation in Hct-MAD2+/– cells after G₁/S synchronization and release into nocodazole. Immunoblot analysis of securin, cyclin B, and actin reveals almost complete securin degradation with no significant loss of cyclin B protein levels in Hct-MAD2+/– cells. The bar graph shows the percentage of cells with a 4N DNA content for the corresponding time points after release from the thymidine block. Black bars, MAD2+/+ cells; gray bars, MAD2+/– cells. (B) Immunoblot analysis of MAD2 protein levels 3 days after further MAD2 depletion by siRNA in Hct-MAD2+/– cells. (C) Cyclin B protein levels after 16 h of exposure to nocodazole added 72 h after the start of transfection.