Figure 1.

Rate of curing and trimming of prion seeds by Sc-Hsp104 is dependent on the [PSI⁺] variant. A, curing of [PSI⁺] by Sc-Hsp104 overexpression was measured in different [PSI⁺] variants. Sc-Hsp104 was expressed from the Gal1 promoter, and the extent of curing was measured at the indicated times by the red/white colony assay. The following variants were used: L1758[PSI⁺], L2888[PSI⁺], 1074[PSI⁺]^DM, 779-6A[PSI⁺]^DM, SY80[PSI⁺], and L1762[PSI⁺]. B, fluorescence imaging of yeast expressing GFP-labeled Sup35 (NGMC) in [PSI⁺] yeast overexpressing Sc-Hsp104. Images are of either the weak L2888[PSI⁺] or the strong SY80 [PSI⁺] variants. Images were taken after overnight incubation in raffinose medium (T = 0), 2 h after addition of galactose medium to induce Sc-Hsp104 expression, or 2 h in galactose medium and 1 h in 5 mm guanidine to stress the cells.