The yeast ZRT1 gene encodes the zinc transporter protein of a high-affinity uptake system induced by zinc limitation.
The yeast Saccharomyces cerevisiae has two separate systems for zinc uptake. One system has high affinity for substrate and is induced in zinc-deficient cells. The second system has lower affinity and is not highly regulated by zinc status. The ZRT1 gene encodes the transporter for the high-affinity system, called Zrt1p. The predicted amino acid sequence of Zrt1p is similar to that of Irt1p, a probable Fe(II) transporter from Arabidopsis thaliana. Like Irt1p, Zrt1p contains eight potential transmembrane domains and a possible metal-binding domain. Consistent with the proposed role of ZRT1 in zinc uptake, overexpressing this gene increased high-affinity uptake activity, whereas disrupting it eliminated that activity and resulted in poor growth of the mutant in zinc-limited media. Furthermore, ZRT1 mRNA levels and uptake activity were closely correlated, as was zinc-limited induction of a ZRT1-lacZ fusion. These results suggest that ZRT1 is regulated at the transcriptional level by the intracellular concentration of zinc. ZRT1 is an additional member of a growing family of metal transport proteins.
Zhao
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Department of Biochemistry and Molecular Biology, School of Medicine, University of Minnesota, Duluth 55812, USA.
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D001483:Base Sequence; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D027682:Cation Transport Proteins; D017931:DNA Primers / Q000737:chemistry; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D012331:RNA, Fungal / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015032:Zinc / Q000378:metabolism*
D002352:Carrier Proteins; D027682:Cation Transport Proteins; D017931:DNA Primers; D005656:Fungal Proteins; D008565:Membrane Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; C098750:ZRT1 protein, S cerevisiae; D015032:Zinc