FIG. 1.

Ume3p regulation by environmental stress. (A) Mid-log-phase RSY10 cultures (glucose) were transferred to the conditions indicated (see Materials and Methods for details). UME3 protein (Ume3p) and transcript levels were determined by Western blot and S1 nuclease protection studies, respectively. ACT1 and Tub1p levels serve as loading controls for mRNA and protein, respectively. The vector lane controls for the nonspecific cross-reactivity of the myc monoclonal antibody. The tRNA lane indicates bands corresponding to nonspecific duplex formation of the S1 nuclease probe itself. (B) Quantitation of the results from panel A were determined from phosphorimager analysis after standardization against Tub1p levels. The values presented are the averages from at least two independent experiments with Ume3p levels in glucose medium being set at 100%. (C) ssa1-lacZ levels in response to stress. Total RNA preparations from the cultures described in panel A were blotted and probed with ³²P-labeled lacZ. Quantitation of the signals was done by phosphorimager analysis, and results are presented relative to the internal ACT1 mRNA controls. ssa1-lacZ levels in glucose prior to stress were set at 100%.