title: The bZip transcription factor Cgap1p is involved in multidrug resistance and required for activation of multidrug transporter gene CgFLR1 in Candida glabrata.
abstract: Transcriptional regulation in response to environmental challenges is crucial for survival of many organisms. In this study, we characterized structural and functional properties of CgAP1, a Saccharomyces cerevisiae YAP1 ortholog, which encodes a transcription factor involved in various stress responses. Deletion of CgAP1 led to decreased resistance to hydrogen peroxide, 4-nitroquinoline-N-oxide (4-NQO), benomyl, and cadmium chloride, which could be fully recovered by reintroduction of an intact CgAP1. CgAP1 was shown to function in S. cerevisiae as it restored the drug resistance of the yap1 mutant. Moreover, overexpression of CgAP1 in a S. cerevisiae wild-type strain increased its resistance to cycloheximide, 1,10-phenanthroline, 4-NQO, and fluconazole. Overexpression of CgAP1 also phenotypically suppressed the drug sensitivity of two Yap1p-regulated transporter mutants, Deltaatr1 and Deltaflr1, to diamide, 4-NQO, and cadmium. Northern blot analysis indicated that Cgap1p regulates the benomyl-induced expression of CgFLR1, a homolog of S. cerevisiae FLR1, which encodes a transporter of the major facilitator superfamily. In contrast to the S. cerevisiae flr1 mutant, deletion of CgFLR1 in C. glabrata only resulted in increased sensitivity to benomyl, diamide, and menadione, but not 4-NQO, cycloheximide, or fluconazole. Taken together, this report demonstrated that CgAP1 plays a critical role in response to various stresses in C. glabrata and reduces the stress through transcriptional activation of its target genes including CgFLR1.
authors.affiliation: Clinical Mycology Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland 20892, USA.
authors.forename: Kuang-Hua
authors.initials: KH
authors.lastname: Chen
authors.forename: Taiga
authors.initials: T
authors.lastname: Miyazaki
authors.forename: Huei-Fung
authors.initials: HF
authors.lastname: Tsai
authors.forename: John E
authors.initials: JE
authors.lastname: Bennett
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D050976:Basic-Leucine Zipper Transcription Factors / Q000502:physiology*; D041221:Candida glabrata / Q000235:genetics / Q000502:physiology*; D026141:Drug Resistance, Multiple, Fungal / Q000235:genetics*; D005260:Female; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D027361:Organic Anion Transporters; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; C118429:FLR1 protein, S cerevisiae; D026901:Membrane Transport Proteins; D027361:Organic Anion Transporters; D029701:Saccharomyces cerevisiae Proteins