The multidrug resistance gene PDR1 from Saccharomyces cerevisiae

The Saccharomyces cerevisiae gene PDR1, responsible for pleiotropic drug resistance, was isolated from a genomic DNA cosmid library by hybridization to the flanking LEU1 gene, followed by subcloning the drug-sensitive phenotype into the transformed pdr1-1, pdr1-2, and pdr1-3 drug-resistant mutants. A RNA molecule of 3.5 kilobases was identified as the PDR1 transcript. The nucleotide sequence of the complementing DNA fragment contained a 3192-nucleotide open reading frame. Disruption of the pdr1 and PDR1 genes restored or increased drug sensitivity. Analysis of the PDR1 deduced amino acid sequence revealed several homologies to four different regulatory proteins involved in the control of gene expression, including a cysteine-rich motif suggested to be a metal-binding domain for DNA recognition. A model is proposed of a general transcriptional control by PDR1 of several target genes encoding proteins from plasma, mitochondria, and possibly other permeability barriers.