MUP1, high affinity methionine permease, is involved in cysteine uptake bySaccharomyces cerevisiae

Using a mutant defective in cysteine uptake, which is resistant to a toxic analog of cysteine, allylglycine, we searched for a gene that complements t he defect in cysteine uptake in a yeast genomic library and found a DNA fra gment causing the recovery; of cysteine uptake and sensitivity to allylglyc ine. The gene in the fragment R;as identical to MUP1, the high affinity met hionine permease gene. We conclude that Mup1 is a major permease in cystein e uptake.