Transcription of lncRNA prt, clustered prt RNA sites for Mmi1 binding, and RNA polymerase II CTD phospho-sites govern the repression of pho1 gene expression under phosphate-replete conditions in fission yeast

Plasmid reporter for dissection of prt control of pho1 expression. The plasmid-borne prt–pho1 cassette (prt⁺) is shown with the mapped transcription start sites of the prt lncRNA and pho1 mRNA (relative to the pho1 AUG start codon) indicated by arrows. Transcription factor Pho7 is required for pho1 transcription and binds to DNA upstream of the pho1 transcription start site. A prtΔ version of the reporter that contains only 283 nt of genomic DNA upstream of the pho1 transcription start site is shown. The prt⁺ and prtΔ plasmids (LEU2) were introduced into pho1Δ yeast cells. Acid phosphatase activity was assayed by conversion of p-nitrophenylphosphate to p-nitrophenol. The y-axis specifies the phosphatase activity (A₄₁₀) normalized to input cells (A₆₀₀). The error bars denote SEM.