Regulation of zinc homeostasis in yeast by binding of the ZAP1 transcriptional activator to zinc-responsive promoter elements

J Biol Chem. 1998 Oct 30;273(44):28713-20. doi: 10.1074/jbc.273.44.28713.

Abstract

Zinc homeostasis in yeast is controlled primarily through the regulation of zinc uptake. Transcription of the ZRT1 and ZRT2 zinc transporters increases in zinc-limited cells, and this induction is dependent on the ZAP1 gene. We hypothesized previously that ZAP1 encodes a zinc-responsive transcriptional activator. Expression of ZAP1 itself increases in zinc-limited cells. This response is also dependent on ZAP1 function through a potential positive autoregulatory mechanism. In this report, we describe the characterization of zinc-responsive elements (ZREs) in the promoters of the ZRT1, ZRT2, and ZAP1 genes. A ZRE consensus sequence, 5'-ACCYYNAAGGT-3', was identified and found to be both necessary and sufficient for zinc-responsive transcriptional regulation. We also demonstrate that ZREs are DNA binding sites for ZAP1. First, a dominant ZAP1 mutation, ZAP1-1(up), which causes increased expression of ZAP1-regulated genes in zinc-replete cells, exerted its effects specifically through the ZREs. Second, electrophoretic mobility shift assays and in vitro DNase I footprint analyses indicated that ZAP1 binds to ZREs in a sequence-specific fashion. These studies demonstrate that ZAP1 plays a direct role in controlling zinc-responsive gene expression in yeast by binding to zinc-responsive elements in the promoters of genes that it regulates.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alleles
  • Base Sequence
  • DNA Primers
  • Gene Expression Regulation
  • Homeostasis*
  • Promoter Regions, Genetic*
  • Saccharomyces cerevisiae Proteins*
  • Signal Transduction
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Transcription Factors
  • Zinc / metabolism*

Substances

  • DNA Primers
  • Saccharomyces cerevisiae Proteins
  • Trans-Activators
  • Transcription Factors
  • ZAP1 protein, S cerevisiae
  • Zinc