Figure 1.

Functional complementation of Zn transport in yeast by ZNT1. A yeast zrt1 zrt2 mutant (zhy3) lacks both high- and low-affinity Zn transporters, and unlike the wild type (wt), requires high-Zn medium for growth. The ZNT1 cDNA ligated into the yeast expression vector pFL61 (denoted pZNT1) restores growth of zhy3 on low-Zn medium (10). Yeast was grown on supplemented minimal medium (14) amended with 0.1% Casamino acids, 20 mg/liter adenine, 20 mg/liter tryptophan, 1 mM EDTA, and 10 μM Fe-EDTA. High- and low-Zn media included 1 mM and 650 μM ZnSO₄, respectively.