FIG. 3.

Activity of the CDR2 promoter carrying a degenerate DRE. (A) Summary of reporter activities of all tested constructs. Growth of the strains carrying the P_(CDR2)-HIS3 constructs was evaluated on MM in the absence or presence of 10 μg/ml estradiol. −, the reporter system is nonfunctional, meaning that the strain containing it is unable to grow in the presence of estradiol or shows constitutive growth even in the absence of estradiol; +, the reporter system is functional, meaning that the growth of the associated strain is identical to that of the positive control carrying wild-type DRE (DSY2673); +/−, reduced growth compared to the positive control. Underlined nucleotides indicate the localization of the DRE core or the putative DRE sequences. Letters in lowercase correspond to the CDR2 promoter sequence flanking the degenerate DRE or the putative DREs of CDR1 and CDR2 coregulated genes; letters in uppercase correspond to the putative DRE sequence; and letters in boldface correspond to transversed nucleotides. (B) Growth of reporter strains carrying degenerate DREs in the P_(CDR2)-HIS3 reporter system. Serial dilutions of overnight cultures were plated onto MM supplemented with histidine (his) or with estradiol. (Top) Numbers 9 to 16 indicate the types of constructs (detailed in panel A) carrying degenerate DREs. (Bottom) P_(CDR2)-HIS3 constructs contained DREs from other gene promoters as indicated in panel A. Plates were incubated for 48 h at 34°C.