Figure 3.

Delineation of the prt2 promoter. A, plasmid reporter of prt2 promoter activity, wherein the pho1 ORF was fused to a genomic DNA segment containing nucleotides −733 (or truncated variants as indicated) to +9 of the prt2 transcription unit. Serial truncations of the upstream margin of the 5′-flanking prt2 DNA were made at −429, −241, −134, −62, and −32 relative to the prt2 transcription start site. The indicated mutations in the HomolD-like and TATA box elements were made in the context of the −241 prt2 promoter. The prt2·pho1 reporter plasmids were placed into [prt2-pho84-prt-pho1]Δ cells. Acid phosphatase activity in phosphate-replete cells was assayed and plotted in bar graph format. B, primer extension analysis of the prt2-driven pho1 transcript and act1 mRNA control was performed with total RNA isolated from cells bearing the indicated reporter plasmids. C, nucleotide sequence of the prt2 promoter reporter is shown from positions −241 to the ATG start codon of the pho1 ORF. The pho1 ATG start codon is in blue and underlined. The prt2 transcription start site is indicated by black arrow above the DNA sequence. Margins of promoter truncations are indicated by red arrows below the DNA sequence. A putative TATA element is outlined by a blue box. A putative HomolD-like element is shaded gold.