Assessments of Ist1 stability. (A) Cycloheximide (CHX) chase experiments using WT and pdr5∆ cells grown to mid-log phase before exposure to 25 mg/l cycloheximide for denoted time before harvesting and immunoblot with ⍺-Ist1 antibodies. (B) Graph of Ist1 stability following cycloheximide chase at indicated times in WT (gray) and pdr5∆ (pink) cells. (C) Growth assays in WT, pdr5∆, pdr5∆ ist1∆ hbt1^∆CHis₆-Ub, and pdr5∆ ist1∆ yeast strains grown to exponentially dividing phase then spotted on YPD (left) and YPD containing 25 mg/liter cycloheximide (right). (D) SDS-PAGE Coomassie stained gels of lysates from BL21(DE3) (upper) or BL21 CodonPlus(DE3) (lower) E.coli strains expressing His₆ control, His₆-Ist1, or His₆-Ist1^KR under T7 promoter control. For each plasmid, two clones are shown from lysates grown to OD₆₀₀ = 0.6, which were grown 16 h at 15°C −/+ 0.5 mM IPTG.