FIG. 4.

Mutations in the Pho2 binding sites differentially affect PHO5 promoter activity. The activities of the wild-type PHO5 promoter fused to the lacZ gene (26) and of promoter variants containing mutations in the Pho2 binding sites were measured as described in Materials and Methods. The activities of the mutated promoter variants are expressed relative to the activity of the wild-type promoter (920 U). The mutations are schematically shown at the bottom.