title: The yeast anaerobic response element AR1b regulates aerobic antifungal drug-dependent sterol gene expression.
abstract: Saccharomyces cerevisiae ergosterol biosynthesis, like cholesterol biosynthesis in mammals, is regulated at the transcriptional level by a sterol feedback mechanism. Yeast studies defined a 7-bp consensus sterol-response element (SRE) common to genes involved in sterol biosynthesis and two transcription factors, Upc2 and Ecm22, which direct transcription of sterol biosynthetic genes. The 7-bp consensus SRE is identical to the anaerobic response element, AR1c. Data indicate that Upc2 and Ecm22 function through binding to this SRE site. We now show that it is two novel anaerobic AR1b elements in the UPC2 promoter that direct global ERG gene expression in response to a block in de novo ergosterol biosynthesis, brought about by antifungal drug treatment. The AR1b elements are absolutely required for auto-induction of UPC2 gene expression and protein and require Upc2 and Ecm22 for function. We further demonstrate the direct binding of recombinant expressed S. cerevisiae ScUpc2 and pathogenic Candida albicans CaUpc2 and Candida glabrata CgUpc2 to AR1b and SRE/AR1c elements. Recombinant endogenous promoter studies show that the UPC2 anaerobic AR1b elements act in trans to regulate ergosterol gene expression. Our results indicate that Upc2 must occupy UPC2 AR1b elements in order for ERG gene expression induction to take place. Thus, the two UPC2-AR1b elements drive expression of all ERG genes necessary for maintaining normal antifungal susceptibility, as wild type cells lacking these elements have increased susceptibility to azole antifungal drugs. Therefore, targeting these specific sites for antifungal therapy represents a novel approach to treat systemic fungal infections.
authors.affiliation: From the Institute of Metabolic Disorders, Genesis Biotechnology Group, Hamilton, New Jersey 08691.
authors.forename: Christina
authors.initials: C
authors.lastname: Gallo-Ebert
authors.forename: Melissa
authors.initials: M
authors.lastname: Donigan
authors.forename: Hsing-Yin
authors.initials: HY
authors.lastname: Liu
authors.forename: Florencia
authors.initials: F
authors.lastname: Pascual
authors.forename: Melissa
authors.initials: M
authors.lastname: Manners
authors.forename: Devanshi
authors.initials: D
authors.lastname: Pandya
authors.forename: Robert
authors.initials: R
authors.lastname: Swanson
authors.forename: Denise
authors.initials: D
authors.lastname: Gallagher
authors.forename: Weiwei
authors.initials: W
authors.lastname: Chen
authors.forename: George M
authors.initials: GM
authors.lastname: Carman
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Nickels
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D000935:Antifungal Agents / Q000494:pharmacology; D002176:Candida albicans / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D041221:Candida glabrata / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D004875:Ergosterol / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005800:Genes, Fungal; D008148:Lovastatin / Q000494:pharmacology; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020218:Response Elements; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013261:Sterols / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D029701:Saccharomyces cerevisiae Proteins; D013261:Sterols; D015534:Trans-Activators; C113958:UPC2 protein, S cerevisiae; D008148:Lovastatin; D006899:Mixed Function Oxygenases; C547779:ERG25 protein, S cerevisiae; D004875:Ergosterol
keywords: Aerobic; Anaerobic; Azole; Candida albicans; Lipid; Lipids; Promoter; Sterol; Transcription; Yeast