Allelism of methionine-sensitive mutants ofSchizosaccharomyces pombeto loci involved in adenine biosynthesis

Abstract

SUMMARYMethionine-sensitive mutants ofSchizosaccharomyces pombewere found to map at 16 loci,min1–min16, seven of which are allelic to knownadeloci involved in adenine biosynthesis. The mutantmin1–106was shown to be located within theade6locus by intragenic recombination analysis. Methionine sensitivity of these mutants is reversible by adenine supplementation and their pigmentation is similar to that of the correspondingademutants. We conclude, therefore, that theseminmutants are incompletely blocked in adenine biosynthesis. These observations further indicate that adenine biosynthesis inS. pombeis inhibited by methionine or a metabolite derived from it. For some otherminmutants showing reversibility of methionine sensitivity by leucine or proline, no allelism to knownleuorproloci was detected.