GSH1, which encodes gamma-glutamylcysteine synthetase, is a target gene for yAP-1 transcriptional regulation.
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.
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Program in Molecular Biology, University of Iowa, Iowa City 52242.
Moye-Rowley
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D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D004271:DNA, Fungal / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D005721:Glutamate-Cysteine Ligase / Q000502:physiology*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D016755:Proto-Oncogene Proteins c-jun / Q000502:physiology*; D012331:RNA, Fungal / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D017931:DNA Primers; D004271:DNA, Fungal; D016755:Proto-Oncogene Proteins c-jun; D012331:RNA, Fungal; D012333:RNA, Messenger; D005721:Glutamate-Cysteine Ligase