(A) Overproduction of Swi1 PrD promotes [SWI+] conversion. As described in the Experimental Procedures, with Swi1-NYFP overproduction (0.5% gal) or without (w/o gal), [SWI+] frequencies were plotted for the indicated 74D-694 strains carrying the PF139-URA3 reporter plasmid. (B and C) The indicated three 74D-694 strains, [PSI+], [PIN+], and non-prion, were co-transformed with p423GAL1-NmCherry and pCUP1-NMGFP (for [PSI+], [PSI+]_S; and non-prion, nonprion_S), or with p423GAL1-NmCherry and pCUP1-RNQ1GFP (for [PIN+], [PIN+]_R and non-prion_R). SC-leu-ura sucrose cultures of the transformants were supplemented with 0.02% (B) or 0.5% (C) galactose and 10 μM CuSO4. After incubation for 48 h, percentages of cells with all types of aggregation (total aggregation) or ring/ribbon-like only aggregation of Swi1-N-mCherry are shown. Statistical analysis for panel A-C was performed by T test (N.S, not significant; **, P<0.01; ***, P<0.001).