FIG. 7.

Pho2 cis elements are required for activation of the PHO5 promoter by Pho2-VP16 and a transcriptionally inactive Pho4 derivative. (A) Activation of the wild-type PHO5 promoter or a promoter variant with a mutated Pho4 site at UASp2 (UASp2-M) by Pho4Δ2 and/or Pho2-VP16 as measured in YS22 (pho2) or YS27 (pho4 pho2). (B) Activation of the PHO5 promoter variants containing mutated Pho2 binding sites, shown schematically at the bottom, by Pho4Δ2 and Pho2-VP16 expressed together in YS27 (pho4 pho2).