FIG. 4.

Complementation of ino4Δ (BRS2004) inositol auxotrophy by various YCp50-INO4 promoter deletions. Respective transformants were plated on uracil-lacking synthetic medium containing inositol and choline and replica plated to uracil-lacking synthetic medium also lacking inositol and choline. Growth is indicated by a plus sign, and absence of growth is indicated by a minus sign. Quantitation of steady-state INO1 mRNA transcript levels by Northern blot hybridization in the wild-type strain (BRS1001) and an ino4Δ mutant strain (BRS2004) transformed with the YCp50-INO4 promoter deletion constructs is shown. Strains were grown in uracil-lacking synthetic medium either containing 75 μM inositol and 1 mM choline (I+C+) or lacking inositol and choline (I−C−). TCM1 was used to normalize for loading variations. The values shown represent ratios of INO1 to TCM1 expression levels. The locations of two putative bHLH binding sites and a potential TATA box are shown as in Fig. 2.