Fig. 6

Analysis of IB1 yeast cells expressing multiple binding units (a) Yeast IB1 cells either transformed with the pYSD-3x-yCup1 plasmid, or carrying one chromosomal copy of the YSD-3x-yCup1 transgene in the ADE2 locus, were analyzed by immunofluorescence microscopy to visualize the localization of the fusion protein. For each strain, micrographs are reported of the differential interference contrast (DIC), the immunofluorescence signal (AF555), the nuclear DNA staining (DAPI), and the merged image. Images are representative of three biological replicates for each yeast strain. Scale bar: 5 μm; (b) 5 × 10⁸ yeast cells of either unmodified IB1 strain (WT), cells expressing triple-tandem yCup1 chimeric protein by multicopy plasmid (pYSD-3x-Cup1), or by single chromosomal copy of the transgene (ade2D::YSD-3x-yCup1), and Cu²⁺ binding was evaluated by ICP-OES, as previously described. Each column represents the mean ± SEM of 4 independent experiments (n = 4; *p < 0,05, Mann Whitney T-test was applied for statistical analysis)