Figure 7.

Core 1 and TR1 are essential cis elements for the promoter function of ste11. Transcription of the ste11–mei2 fusion gene driven by variously modified ste11 promoters was examined by Northern blot analysis. Cells harboring each reporter construct on a plasmid were harvested either during vegetative growth (+nitrogen) or after being starved of nitrogen (−nitrogen). RNA was prepared from each sample and analyzed by the mei2 probe. (A) Lanes 1 and 2, expression from the wild-type promoter (pDM+); lanes 3 and 4, mutant in core 1 (pDM3); lanes 5 and 6, mutant in core 2 (pDM4); and lanes 7 and 8, mutant in both core 1 and core 2 (pDM34). (B) Lanes 9 and 10, expression from the wild-type promoter (pDM+); lanes 11 and 12, mutant in TR1 (pDM1); lanes 13 and 14, mutant in TR2 (pDM2); and lanes 15 and 16, mutant in both TR1 and TR2 (pDM12). The major transcript of the reporter gene is indicated by the arrowhead. rRNA stained with ethidium bromide is shown in the lower panels as loading controls. The relative intensity of transcription is presented under the top panels.