Figure 8. hcr1Δ and eIF3 mutants genetically interact with release factor mutants.

(A–B) The sup45^Y410S mutation eliminates the negative impact of hcr1Δ on (A) read-through and (B) growth rates. The hcr1Δ strain was crossed with the sup45^Y410S mutant strain and the resulting double mutant was transformed with sc SUP45, hc HCR1, or empty vector (EV), respectively, and (A) processed for stop codon read-through as described in Figure 1 (hcr1Δ read-through values were set to 100%) or (B) subjected to a growth spot assay at indicated temperatures for 2 or 3 days. (C–D) Combining the selected TIF32 mutants with sup35^N536T and sup45^Y410S (C) reduces their read-through defects and (D) produces synthetic growth phenotypes. The wt and mutant alleles of TIF32 were introduced into tif32Δ, sup35^N536T tif32Δ, and sup45^Y410S tif32Δ strains, respectively, by plasmid shuffling. (C) The resulting double mutant strains were grown in SD and processed for the stop codon read-through as described in Figure 1 (the read-through values of both single eRF mutants were set to 100%), or (D) spotted in four serial 10-fold dilutions on SD medium and incubated at indicated temperatures for 4 days. ND; not determined due to severe growth deficiency.