Figure 1. Dissection of FLO11 promoter and construction of plasmid-based [SWI⁺] reporters for S288C strains.

(A) A diagrammatic illustration of the wild-type and truncation mutant FLO11 promoters. The 3-kb FLO11 promoter (P_FLO11) spans 15 0.2-kb segments carrying 7 upstream repression sequences (URSs, −) and 5 upstream activation sequences (UASs, +). The dotted lines stand for regions that are deleted. Construction strategies are shown in Figure S1. (B) A diagram showing the structure of constructed reporter plasmids. URA3 gene serves as a reporter gene driven the wild type or a truncated FLO11 promoter shown in A. CYC1 terminator was included for all the constructs. 50-bp upstream and downstream extensions of LYS2 flank the reporter to provide an option to integrate a reporter into chromosome. (C) BY4741 non-prion strains with the indicated genotypes were transformed with individual p415-based URA3 reporter plasmids. Cells were spotted onto synthetic complete (SC) selective plates without uracil. Images were taken 3 days post spotting. Shown is a representative result of at least three independent experiments. (D) The indicated FLO8 or flo8 strains with distinct Swi1 status were transformed with either P_F139-URA3 or P_F19-URA3 plasmid and assayed for growth on glucose-containing SC medium (glucose) without uracil (−uracil), or with 5-FOA (+5FOA). Raffinose plate (glucose-free) was also included to verify the Swi1 status. Shown are representative results (3 days post-spotting) of at least three repeated tests.