ISOLATION AND CHARACTERIZATION OF YEAST MUTANTS AUXOTROPHIC FOR 2'-DEOXYTHYMIDINE 5'-MONOPHOSPHATE

Mutant strains of Saccharomyces cerevisiae auxotrophic for deoxythymidine monophosphate (dTMP) were isolated and characterized. Two distinct classes of auxotrophs were obtained. One class had a simple requirement for dTMP and was analogous to thymine-requiring bacteria. The second class required dTMP, adenine, histidine and methionine and this complex nutritional phenotype was due to defects in folate metabolism. The dTMP-dependent growth of respiratory-competent grande auxotrophs was found to be markedly affected by media composition and carbon source. In the absence of dTMP thymineless death occurred in both mutant classes. © 1979 Springer-Verlag.