Interactions between chromosomal omnipotent suppressors and extrachromosomal effectors in Saccharomyces cerevisiae.

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