Figure 2. Lactic acid induced [GAR+] has the same prion-like features as spontaneous [GAR+].
(A) Dominance in crosses between [GAR+] strains and [gar−] strains is seen in colonies isolated from a GLY + GlcN plate (spontaneous [GAR+]), as well as those induced with 0.1% D-lactic acid (LA-induced [GAR+]). Five-fold serial dilutions are shown for three biological replicates; orange coloring indicates strains exhibiting the [GAR+] phenotype. (B) Lactic acid-induced cells can be cured of the [GAR+] phenotype with transient expression of a dominant negative Hsp70 variant (Ssa1-K69M or Hsp70DN). Single colonies were propagated alone or with a plasmid expressing Hsp70DN for ~125 generations, bottlenecked each ~25 generations. After verifying plasmid loss, colonies were again tested for their capacity to grow on GLY + GlcN medium. Each image shows five-fold serial dilutions for three biological replicates. (C) A strain with diminished expression of PMA1, pma1-DAmP, has reduced spontaneous [GAR+] acquisition and is not induced by lactic acid. Lactic acid-induction frequencies differ from those in Figure 1C due to strain background BY4741, which has a lower frequency of [GAR+] acquisition (Brown and Lindquist, 2009). Plotted as in Figure 1C.
Figure 2—figure supplement 1. Both spontaneous and lactic acid-induced [GAR+] diploids transmit the phenotype through meiosis to nearly all spores, demonstrating non-Mendelian inheritance.
Figure 2—figure supplement 2. Both spontaneous [GAR+] cells and lactic acid-induced [GAR+] S. cerevisiae cells exhibited sensitivity to the Hsp70 inhibitor myricetin (50 μM) on GLY + GlcN medium.
