Nonsense suppressors of yeast cause osmotic-sensitive growth

Many nonsense suppressors of Saccharomyces cerevisiae cause growth inhibition on hypertonic media. Eight tyrosine-inserting UAA (ochre) suppressors, eight tyrosine-inserting UAG (amber) suppressors, a leucine-inserting UAG suppressor, and a serine-inserting recessive lethal UAG suppressor cause osmotic sensitivity, whereas a serine-inserting UAA suppressor does not cause sensitivity. Although the mechanism is not understood, the growth inhibition of specific suppressors on hypertonic media is correlated with their efficiencies of suppression. This heretofore unknown property of nonsense suppressors is useful for mitotic mapping, selecting tRNA mutants, selecting antisuppressors, and scoring nonsense suppressors.