Premium
Zinc deficiency response in Saccharomyces cerevisiae : Characterization of the Zap1‐responsive regulon
Author(s) -
Wu ChangYi,
Bird Amanda,
Winge Dennis,
Eide David
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.782.14
Subject(s) - biology , gene , transcription factor , genetics , promoter , saccharomyces cerevisiae , gene expression
The yeast Zap1 transcription factor is a central player in zinc homeostasis. To identify genes important for low zinc growth, DNA microarrays were used to identify genes directly regulated by Zap1. A previous study indicated that Zap1 activates expression of 46 genes under moderate zinc deficiency. Our new experiments identified Zap1 targets that respond only to severe deficiency. We also applied motif identification tools to find candidate Zap1 binding sites (ZREs) in the promoters of these genes. Using these methods, we found 31 new Zap1 target genes. We confirmed the expression levels of several by S1 nuclease protection assay and verified Zap1 binding to putative ZREs by EMSA. We also identified 36 genes that are repressed in a Zap1‐responsive manner. Among these genes, MET3/14/16 encode enzymes of sulfur assimilation. It was known that these genes are regulated by the Met4 transcriptional activator via ubiquitination by Met30, a component of SCF ubiquitin ligase. We found that MET30 is a Zap1 target up‐regulated under severe zinc deficiency. We also showed that less Met4 protein accumulates in zinc‐limited cells and in cells expressing a constitutive Zap1 allele. These results suggest that MET3/14/16 genes repression is due, at least in part, to Met4 down‐regulation following MET30 induction by Zap1. Hence, Zap1‐mediated repression may control sulfur assimilation during the zinc deficiency.