Exploring the ability of cyanobacterial ferric uptake regulator (FUR) proteins to increase yeast tolerance to abiotic stresses

Ferric uptake regulator (FUR) proteins are involved in the regulation of genes related to metal homeostasis and the oxidative stress response in most prokaryotes. The cyanobacterium Anabaena sp. PCC 7120 contains three FUR paralogs: FurA, FurB, and FurC. Previous studies demonstrated that overexpression of FurA and FurB increased oxidative stress tolerance in Escherichia coli. Hereby, we analyzed the effects of FurA and FurB expression in Saccharomyces cerevisiae. We tested the tolerance of the yeast strains expressing these cyanobacterial genes against common abiotic stresses: divalent metals, oxidative stress inducers, membrane damaging reagents, and salt. Both strains exhibited either the same or lower growth than the control under most of the conditions tested. However, the FurA-derivative strain showed better growth under oxidative stress induced with low concentrations of hydrogen peroxide and t-butyl hydroperoxide. The FurB-derivative grew better than the control under a broader range of oxidative conditions. To our knowledge, this is the first report demonstrating that FUR proteins may increase oxidative stress tolerance when heterologously expressed in a eukaryotic organism.