The Gcn4E binding site contributes to the activation of Ty1 transcription by Gcn4. (A) β-Galactosidase activities of the different HIS4-lacZ constructs in strains grown under normal conditions or under conditions of histidine starvation. 3AT was added to the cultures as described in the legend to Fig. 5A. GCN4, strain LV555 transformed with pAM19 (GCN4 HIS3 CEN); gcn4Δ, strain LV555 transformed with pRS313; WT, HIS4-lacZ fusion; ΔUAS, HIS4ΔUAS-lacZ fusion; 3H, HIS43H-lacZ fusion; 3L, HIS43L-lacZ fusion. The different HIS4-lacZ constructs are carried on 2μm URA3 plasmids as described in Materials and Methods. LV555 is a Y328 derivative. (B) Gel retardation assays. 3H, DNA probe containing 3 copies of the Gcn4E motif; 3L, DNA probe without the Gcn4E motif. Gcn4, purified His-tagged Gcn4 protein; +c, cold competitor (250 ng of pHIS43H-lacZ); I, II, and III, His-tagged Gcn4/DNA complexes.