Interactions between chromosomal omnipotent suppressors and extrachromosomal effectors in Saccharomyces cerevisiae

Chromosomal omnipotent suppressor mutations recovered in ψ⁺ strains of Saccharomyces cerevisiae were brought into ψ^- cytoplasm. SUP46, SUP138 and SUP139 acted as dominant omnipotent suppressors in the ψ^- cytoplasm though their suppressor activity was substantially reduced. SUP46 and SUP138 conferred recessive thermosensitivity and antibiotic sensitivity in ψ^- cytoplasm as in ψ⁺ cytoplasm. On the other hand, sup111 through sup115, which acted as recessive omnipotent suppressors in the ψ⁺ cytoplasm, manifested no, or very low, suppressor activity in the ψ^- cytoplasm. They, however, still enhanced the efficiency of the SUP29 tRNA suppressor in ψ^- cytoplasm. A multicopy plasmid carrying the wild-type SUP35 gene enhanced the efficiency of sup111 in ψ^- cytoplasm.