FIG. 4.

Results from Northern blot hybridization experiments using SPI1 as probe and the actin-encoding gene, ACT1, as the internal control. Total RNA was extracted from cells of S. cerevisiae BY4741 (WT) harvested during cultivation under 2,4-D stress (0.3 mM) (A). Growth was monitored by measuring culture OD₆₀₀. Relative SPI1 mRNA/ACT1 mRNA ratios were obtained by densitometry of the autoradiograms (B) and are average values from three experiments. The relative mRNA ratio immediately before cell exposure to the herbicide (0 h) was set as 1.