Hap1 Activity in ydj1 Mutant Strains
To assay Hap1 activity, strain JJ261 expressing wild-type YDJ1, ydj1-104, or the indicated Ydj1–Sis1 fusion protein was transformed with a UAS1/CYC1-lacZ reporter plasmid (Guarente et al. 1984). After overnight incubation at 25°C in the presence of high concentrations of δ-aminolevulinic acid (ALA) (250 μg/ml), β-galactosidase assays were performed as described (Johnson and Craig 2000).