FIG. 3.

Chromatin structure of the ARO4-HIS7 intergenic region at low and high intracellular Gcn4p levels. Yeast cells were grown in the presence of 0.3 mM adenine to prevent Bas1p/Bas2p-mediated HIS7 transcription. The Mnase protection pattern as described in Fig. 2 for cells with basal HIS7 expression levels of strain FY1353 can be seen in lanes 1 and 2. Strain FY1353[p238] expresses constitutively high amounts of Gcn4p and yields a protection pattern as shown in lanes 5 and 6. In lanes 3 and 4, restriction digests with Sau3A and XbaI/TaqI show DNA fragments precisely located within the HIS7 promoter. The diagram on the left and the black ramps at the bottom are as described for Fig. 2.