FIGURE 1.

CHA1 induction depends on the Swi/Snf complex. A, schematic diagram of the CHA1 promoter. The dashed ellipse represents the nucleosome that occludes the TATA element in the uninduced promoter and is remodeled upon activation. B, CHA1 expression in CSM containing 1 mg/ml of serine was measured by Northern analysis and normalized to PYK1 mRNA in wild type (BY4741) and deletion mutants as indicated. Error bars represent S.D. (n = 4). C, CHA1 expression in CSM containing 1 mg/ml of serine was measured by Northern analysis and normalized to 26 S rRNA in wild type (BY4741) and snf/swi deletion mutants as indicated. Error bars represent S.D. (n = 4). D, delayed induction kinetics of CHA1 in snf5Δ and swi3Δ yeast. Transcription was halted by addition of 10 mm sodium azide at the indicated times following addition of 1 mg/ml of serine to yeast cultures grown in CSM, and RNA analyzed by Northern blotting. Error bars represent S.D. (n = 2–4; note n = 4 for t = 0, 5, 15, 30, and 60 min (left panel)). For the kinetic analyses in D, data were normalized to allow easier visual comparison (see “Experimental Procedures”); this erases the difference in transcription level between wild type and mutant, which was otherwise consistent with that in C.