FIGURE 3.

Instability of the C-terminal domain of BRCA1. A, Western blot analysis of the abundance of the C-terminal domain of BRCA1 and the β-actin control. The C-terminal domain of BRCA1 was expressed in HEK 293T cells using the Ub-BRCA1 construct to expose the endogenous N-terminal aspartate. Transfected cells were harvested at the indicated times after the addition of cycloheximide. Additional controls include a mock transfection and a vector control. B, analysis of three individual experiments reveals a protein half-life of ∼3 h. C, Western blot analysis reveals that the degradation of the C-terminal domain of BRCA1 is blocked by the co-treatment of the cells with the proteasome inhibitor, MG132.