FIG. 1.
Experimental strategy. (A) Schematic depiction of two chromatin reporter plasmids, TALS and TA17Δ80. UASGAL3 is a single Gal4p binding site from the GAL3 promoter (3), and UAS17 is a single near-consensus Gal4p binding site (21) introduced in the TRP1ARS1 derivative TA17Δ80 (48). Only nucleosomes I and II have been shown to be well positioned in TA17Δ80, and so the remaining nucleosomes are not numbered. (B) Scheme for placing Gal4p synthesis under hormonal control. aa, amino acids. See text for details. (C) The chimeric activator LexA-ER-VP16 was tested for activity at a CYC1-lacZ reporter gene having two, four, or eight LexA binding sites upstream. Yeast cells (YJ0α) grown in raffinose medium to mid-log phase were incubated for 3 h after addition of 100 nM β-estradiol before measurements of β-galactosidase activity for plus-hormone samples. The results shown are an average from three independent colonies from each of two independent transformations.