FIG. 3.

(A) Direct measurement of the t_1/2 of the mRNA encoding L30. Strain JV7-2a (rpl30Δ::HIS3 [pYE: CEN, URA3 GAL1-RPL30]) was grown at 37°C in YPGal medium and shifted to YPD (4% dextrose) as described in Materials and Methods. Cells were harvested just before and at intervals after the shift, and RNA was prepared and analyzed by Northern blotting as described previously. After PhosphorImager analysis, the t_1/2 of the GAL1, GAL10, and GAL-RPL30 mRNAs was determined by using the stable U3 RNA as a loading control (Table 2). Note that the same experiment was carried out at 23°C, in which case the t_1/2 of the mRNAs was about twice as long. (B) Extended t_1/2 of the GAL1 and GAL10 mRNAs in an rpb1-1 strain. Strain Y260 (rpb1-1) was grown in YPGal medium at 23°C. At zero time, one sample was taken; half the remaining culture was shifted to 37°C, and the other half was filtered and resuspended in YPD (4% dextrose), prewarmed, and maintained at 37°C. Samples were taken at the indicated times, and RNA was prepared and analyzed as for panel A.