Figure 6.

The double mutant hsf1^ts skn7Δ is hypersensitive to hydrogen peroxide. Sensitivity to hydrogen peroxide was assayed for W303-1a and isogenic skn7Δ, for MYY290 (HSF1⁺) and the hsf1^ts derivative MYY385, and for an hsf1^ts skn7Δ spore clone (DR20-2b) derived from a cross between skn7Δ and MYY385. Cell suspensions were streaked on a YPD plate (Control) and a YPD plate onto which 1 μl of 7.7 M t-butyl hydrogen peroxide was spotted on a disk of Whatman 3MM paper positioned in the center of the plate (+ hydroperoxide). Suppression of hypersensitivity was judged by the ability to grow in the presence of hydrogen peroxide of a YCplac111 (Gietz and Sugino, 1988) plasmid expressing the SKN7 gene (+SKN7) or an SKN7^D427N mutant (+ SKN7-DN) in which the conserved aspartate residue (D427) was mutated to asparagine. The hsf1^ts skn7Δ strain was also transformed with the YCplac111 vector alone (+ vector); plates were incubated for 2 d at 30°C.