Fig 5. Manipulations expected to increase tRNAPhe levels link suppression of the trm7Δ growth defect with reduction of GAAC induction.
(A) Overexpression of tRNAPhe(GAA) reduces induction of the GAAC response. WT or trm7Δ strains containing a high-copy [2μ LEU2] plasmid expressing tF(GAA), tL(UAA), tW(CCA) or a vector as indicated were grown in SD-Leu at 30°C to mid-log phase, and mRNA was isolated and analyzed for relative HIS5 mRNA levels. (B) A maf1Δ mutation suppresses the growth defect of a trm7Δ mutant. WT and trm7Δ [CEN URA3 TRM7] strains with or without a maf1Δ mutation, as indicated, were grown overnight in rich media, and analyzed by spotting to media containing 5-FOA, and incubation for 2 d at 30°C. Strains from the 5-FOA plate were then purified on medium containing 5-FOA, grown overnight in YPD, diluted, spotted on plates as indicated, and incubated for 2 d at 30°C.