In Saccharomyces cerevisiae ρ0 Cells, UME6 Contributes to the Activation of ABC Transporter Genes and Pleiotropic Drug Resistance via RPD3 and PDR3

Abstract

In Saccharomyces cerevisiae, the Rpd3L complex includes the histone deacetylase Rpd3 and the DNA binding proteins Ume6 and Ash1 and serves as a transcriptional silencer or enhancer. In S. cerevisiae, the transcription of PDR5, which encodes a major drug efflux pump, and pleiotropic drug resistance (PDR) are hyperactivated by the transcription factor Pdr3 in ρ0/− cells, which lack mitochondrial DNA. We previously showed that RPD3 and UME6 are required for the activation of PDR5 transcription and PDR in S. cerevisiae ρ0 cells. Here, using real-time PCR analysis, we revealed that RPD3 and UME6 are responsible for the activated basal expression of the ABC transporter-encoding genes SNQ2, PDR15, and PDR5 in S. cerevisiae ρ0 cells. Furthermore, using real-time PCR analysis and a spot dilution assay, we found that Ume6 increases the basal expression of PDR5 and PDR15 and induces PDR in a manner dependent on RPD3 and PDR3 in ρ0 cells. This finding may contribute to the elucidation of the relationships between the molecules required for the activation of ABC transporter genes in S. cerevisiae ρ0/− cells and in pathogenic Candida species.