Uptake of DNA by fragile mutants of Saccharomyces cerevisiae.

When Saccharomyces cerevisiae SY15 rho° mutant cells grown in media stabilized with 10% sorbitol were suspended in 2% sorbitol solutions, 60-70% of the population did not lyse and became permeable to native high molecular weight DNA. Maximal incorporation of DNA to DNase resistant state was measured after 60 min of incubation in presence of 5 μg/ml DNA and 10 mM CaCl2. These results suggest that the fragile mutants might be tested as hosts for transformation of whole yeast cells.