FIG. 5.

Turnover of c-Myb in COS-7 cells in the absence or presence of the 26S proteasome inhibitor, ALLN. COS-7 cells were transiently transfected with pcDNA3.1 expressing full-length c-Myb, and after 36 h the cells were pulse-labeled with [³⁵S]methionine-[³⁵S]cysteinine and chased for the indicated times. ALLN (N-acetyl-l-leucinyl-l-leucinyl-norleucinal) dissolved in dimethyl sulfoxide (DMSO) was added for the last 15 min of the pulse and kept at the same concentration during the chase. Cells treated with 0.5% dimethyl sulfoxide were used as a negative control for this experiment.