Figure 3.

[PSI⁺] is propagated cryptically in NatA null strains. (A) A [PSI⁺] strain disrupted for both ARD1 and NAT1 (Δard1Δnat1, SY319) was transformed with empty vectors (vector), an empty vector and an expression plasmids for ARD1 (pAA2241) or NAT1 (SB208), or ARD1 and NAT1 together (ARD1 + NAT1) and plated on minimal media lacking uracil and leucine (SD−ura−leu) to select for the plasmids or minimal media lacking uracil, leucine, and adenine (SD−ura−leu−ade) to select for the plasmids and for the [PSI⁺] phenotype. (B) Diploid strains resulting from the following crosses, strong [PSI⁺] × [psi⁻], weak [PSI⁺] × [psi⁻], [psi⁻] × [psi⁻], Δnat1Δard1 (SY319) × [psi⁻], were plated on ¼ YEPD (YPD) or minimal media lacking adenine (SD-ade) to select for the [PSI⁺] phenotype.