Fig. 2.

Inducible genes required Yta7 and its AAA-ATPase domain for proper expression. (A) RNA analysis of SK1 WT and yta7Δ homozygotes. Cells were pregrown in YPAcetate, represented by the t = 0 time point, and then resuspended in sporulation medium for the times indicated. (B) RNA analysis of galactose induction. Cells were grown in YPRaffinose (2%, non-inducing) to an OD₆₀₀ of 0.6; at that point, cells were harvested for the t = 0 time point. Prewarmed galactose was then added to a final concentration of 2%. (C) RNA analysis was performed as above, except cells were harvested after 1 h with galactose. (D) Mating test of α-cells. WT is unable to mate if the “Boundary,” 1 kb of DNA normally to the right of HMR, is inserted between the HMR-E silencer and a1, denoted HMR-E-Boundary-a1. This mating defect is because Sir proteins cannot traverse this Boundary to silence a1. When the yta7Δ mutation is introduced into this background, mating is partially restored (26), indicating that the Boundary is partially defective.