GSH1, Which Encodes γ-Glutamylcysteine Synthetase, Is a Target Gene for yAP-1 Transcriptional Regulation

Abstract

Changes in gene dosage of the YAP1 gene, encoding the yAP-1 transcriptional regulatory protein, cause profound alterations in cellular drug and metal resistance. Previous studies on yAP-1 action in yeast cells have used the AP-1 response element (ARE) from simian virus 40 as an artificial site for yAP-1-mediated transcriptional activation. No authentic yeast target sites for control of gene expression by yAP-1 are known. Here we show that the GSH1 gene, encoding gamma-glutamylcysteine synthetase, is transcriptionally responsive to the yAP-1 protein. GSH1 encodes the rate-limiting step in yeast glutathione biosynthesis and contains within its promoter region a DNA element that matches the ARE in 11 of 12 positions. The GSH1 yAP-1 response element (YRE) was recognized by yAP-1 protein in vitro. Northern (RNA) blot analysis showed that GSH1 mRNA levels were responsive to YAP1 gene dosage. A site-directed mutation in the YRE that blocked yAP-1 binding in vitro prevented the mutant GSH1 promoter from responding to elevation in YAP1 gene dosage. A delta gsh1 mutant strain was constructed and unable to grow in the absence of exogenous glutathione. A mutant GSH1 gene lacking the YRE was unable to confer normal cadmium tolerance, although other yAP-1-mediated phenotypes remained normal. Thus, GSH1 is one of several genes that are transcriptionally controlled by yAP-1 and influence drug resistance.

Diphenyl Diselenide Protects against Methylmercury-Induced Toxicity in Saccharomyces cerevisiae via the Yap1 Transcription Factor

“…36,37 The Yap1 transcription factor is involved in GSH1 transcription activation and increases the expression of SOD1 and CAT1 genes after exposure to H 2 O 2 . 38,39 Yap1 was also demonstrated to regulate ATP-binding cassette (ABC) transporters in yeast. Members of the ABC superfamily catalyze the ATP-dependent transport of chemically diverse compounds across cellular membranes, including the plasma membrane or intracellular organellar membranes.…”

Enrichment of Yeast Thioredoxin by Green Tea Extract through Activation of Yap1 Transcription Factor in Saccharomyces cerevisiae

“…However, both drugs are not classified as the chemicals provoking oxidative stress. On the other hand, both GSH1 and GSH2 , coding for γ-glutamylcysteine synthetase and glutathione synthetase, respectively, which are the enzymes responsible for GSH biosynthesis, are among the Yap1 targets ( , ). GSH functions as an antioxidant by supplying electrons to the glutathione peroxidase reaction.…”

Soft Cysteine Signaling Network: The Functional Significance of Cysteine in Protein Function and the Soft Acids/Bases Thiol Chemistry That Facilitates Cysteine Modification

“…68 The presence of two cysteine rich clusters that respond preferentially to different types of stress suggests that the type of Yap1 cysteine modification has downstream implications on gene regulation. Indeed, hydrogen peroxide activated Yap1 up-regulates the expression of genes whose products include antioxidants and components of thiol-reducing pathways including TRX2, 159 γglutamylcysteine synthetase (GSH1), 160 glutathione reductase (GLR1), 161 and cytosolic catalase T (CTT1). 68 It has been demonstrated that yeast deficient in the SKN7 gene are also hypersensitive to oxidative stress, 162 underscoring the complexity of overlapping molecular defenses against oxidative stress.…”