Figure 2

Transformation of SP14NM protein into yeast induces [ PSI⁺] only after fiber formation. The [PSI⁺] phenotype was assayed by color on YPD, growth on SD-ADE and curability (not shown). Control protein transformations show that protein harvested from either strong or weak [PSI⁺] cells transformed in to [psi^-] cells induces the corresponding prion phenotype while protein harvested from [psi^-] cells does not induce the prion state. Soluble SP14NM protein (SP14NM^sol) does not induce the [PSI⁺] prion phenotype prior to fiber formation. SP14NM protein was able to induce the [PSI⁺] prion phenotype after fiber formation either at 4°C (SP14NM⁴, strong strain) or 25°C (SP14NM²⁵, weak strain).