A, Northern blot analysis was carried out on RNA from DY500, DY510, DY520 (WILD TYPE); DY501, DY511, DY521 (dst1); DY502, DY512, DY522 (rpb2–10); and DY503, DY513, DY523 (rpb2–10 dst1) yeast untreated (−) or treated with 75 µg/ml 6AU (+) for 30 min and challenged with galactose for 1 h. The blot was probed with the PCR product 3′ of the Ia site, shown in Fig. 6. Arrows indicate the full-length transcripts produced by the different plasmids. B, the means and standard deviations (n = 3) were calculated, normalized to the level of transcript in untreated wild-type cells containing pYES2, and plotted.