FIG. 3.

Effect of expression of various Gal4 fusion activators on the replication of an ARS1 plasmid whose B3 element was replaced by a Gal4 binding site. (A) Schematic representation of the Gal4 fusion proteins. (B) Capacity of each fusion protein to stimulate transcription. The plasmids expressing the indicated Gal4 fusion proteins were transfected into the yeast SFY526 strain, which had the β-galactosidase gene linked to the GAL1 promoter, and the enzymatic activity of β-galactosidase in the transfected cells was assayed. (C) Capacity of each fusion protein to stimulate replication. The plasmids expressing the indicated Gal4 fusion proteins were cotransfected with the mutant ARS1 plasmid (B3/Gal4 [pHK803]) containing the Gal4 binding site in place of the B3 element. Replication activity was measured by the DpnI assay as described in Materials and Methods, and the results of at least two independent experiments and the relative amounts of the replicated molecules are indicated. Open bars and different patterns indicate the Gal4 DNA binding domain and the protein fused to the Gal4 DNA binding domain, respectively.