ATPase-defective MOT1 represses basal transcription. (A) Basal transcription reactions were performed as described in the legends to Fig. 2 and 3 except that reaction mixtures contained 10 ng (lane 2), 30 ng (lane 3), 100 ng (lane 4), 300 ng (lane 5), or 1,000 ng (lane 6) of MOT1 K1303A. The reaction mixture in lane 1 contained no added MOT1 K1303A. The bands that were quantitated are indicated by the arrows. (B) Quantitation of the data shown in panel A.