Fig. 5.

Effect of the different Haa1 modifications on the time courses of transcription levels of the HAA1 gene, four genes belonging to the Haa1-regulon (TPO2, TPO3, YRO2 and YGP1), and a reference gene (FPS1) whose expression has been shown to be not affected by acetic acid. Cells were cultivated in synthetic medium without acetic acid until exponential phase (time point 0) and then transferred to synthetic medium containing 50 mM acetic acid (pH 4.5). Immediately before and 30, 60 and 120 min after exposure to acetic acid, aliquots of the cell suspension were taken to determine the respective mRNA levels by real-time RT-PCR. Values represent the average of at least three independent experiments, and ACT1 mRNA level was used as an endogenous control. The mRNA level measured in cells of the wild-type CEN.PK113-7D strain (Haa1^WT) cultivated in the absence of acetic acid was set as 1 and used to normalize the mRNA levels determined in the other strains and conditions. The corresponding growth curves recorded by OD₆₀₀ measurement are also shown