FIG. 4.

New protein synthesis is not required for Ume3p destruction in response to stress. A log-phase culture (RSY10) harboring pKC337 was split, and one-half was treated with cycloheximide for 30 min. Both untreated (lanes 1 to 3) and treated (lanes 4 to 6) cultures were split again and either harvested directly (lanes 1 and 4) or subjected to ethanol (lanes 2 and 5) or oxidative (lanes 3 and 6) stress as described in the Fig. 3 legend. Protein extracts were prepared, and Ume3p levels (arrow) were determined as described in Materials and Methods. Tub1p levels were used as loading controls.