Fig. 4. The TAF_II-dependent region of RNR3 maps to the damage-responsive elements (DREs). (A) Schematic representations of the chimeric promoters (above). The positions of the DREs are indicated by the black bars above the RNR3 promoter and are located at –213, –261 and –323 relative to the major transcription start site. The TATA boxes are located at RNR3, –75, ADH1, –91. Yeast strains transformed with the plasmids indicated on the right hand side of the panel were grown at 23°C to midlog (0), transferred to 37°C for 45 min, and MMS was added to a final concentration of 0.015% to cells containing RNR3^FL-LacZ, RNR3^core-LacZ and RNR3^US-ADH1^coreLacZ. Cells were withdrawn for RNA isolation after 1.5 and 3 h. LacZ RNA was detected by northern blotting. Note that the lacZ transcript marked with an asterisk originates from the TSM1 expression plasmid, pRS313-TSM1. (B) The same as (A), but using a construct containing a synthetic tandem array of four DREs (Xs) from the RNR2 promoter positioned upstream of the ADH1 core promoter.