Genetic expression of bacterial merC fused with plant SNARE in Saccharomyces cerevisiae increased mercury accumulation

MerC encoded by merC in the Tn21 mer operon, is a heavy metal transporter that may be a useful molecular tool for the bioremediation of cadmium and mercury. To regulate subcellular localization, the Arabidopsis SNARE proteins SYP111 and AtVAM3 were fused to the C-terminal end of MerC. In Saccharomyces cerevisiae, green fluorescent protein (GFP)-MerC-SYP111 fusion proteins located primarily to the plasma membrane, whereas GFP-MerC-AtVAM3 was detected in the vacuolar membranes. These results suggest that SYP111 and AtVAM3 direct MerC fusion proteins to the plasma and vacuolar membranes, respectively. Yeast cells expressing MerC-SYP111 accumulated significantly more mercury than control cells or cells expressing MerC-AtVAM3. Thus, it is possible that localizing MerC to the plasma membrane of plants may represent a similarly promising strategy for improving phytoaccumulation and sequestration of mercury at polluted sites.

► We demonstrate Arabidopsis SNAREs can be used as organelle-targeting markers to direct bacterial heavy metal transporter, MerC, to specific membranes in the model eukaryotic organism, yeast.
► We show yeast genetically engineered to express MerC in its plasma membrane accumulated significantly more mercury than the control cells.
► The use of plant SNARE to direct metal transporter MerC to particular membrane may open new avenues for designing and improving biomass to be more suitable for use in the environmental remediation of toxic metals.