Isolation of aCandida albicans gene, tightly linked toURA3, coding for a putative transcription factor that suppresses aSaccharomyces cerevisiaeaft1 mutation

A pathogen such as C. albicans needs an ef®cient mechanism of iron uptake in an iron- restricted environment such as is the human body. A ferric-reductase activity regulated by iron and copper, and analogous to that in S. cerevisiae, has been described in C. albicans. We have developed an in-plate protocol for the isolation of clones that complement an aft1 mutation in S. cerevisiae that makes cells dependent on iron for growth. After transformation of S. cerevisiae aft1 with a C. albicans library, we have selected clones that grow in conditions of iron de®ciency and share an identical plasmid, pIRO1, with a 4500 bp insert containing the URA3 gene and an ORF (IRO1) responsible for the suppr…