Objective: The aim of this study was to investigate experimentally the roles of iron transport-related genes involved in iron-resistance mechanism, using the iron-resistant yeast Saccharomyces cerevisiae as a model organism.

Materials and Methods: S. cerevisiae M8FE strain previously made resistant to iron ion in our previous studies was used with S. cerevisiae CEN.PK113-7D reference strain. The expression levels of AFT1, FET3, FET4, COT1, CCC1 and ZRC1 genes known to be related to iron ion transport were comparatively determined under control, low (1 mM) and high (15 mM) iron-stress conditions, using real-time, quantitative polymerase chain reaction (q rt-PCR) method.

Results: Among the investigated genes, FET3 had the highest variation in expression levels. In the presence of 1 mM iron-stress, FET3 expression increased in iron stress-resistant M8FE strain up to about 16-fold of the reference strain under control conditions whereas it increased to about three-fold at high (15 mM) level of iron-stress. Generally significant increases were also observed in CCC1 and COT1 gene expression levels. AFT1 expression levels decreased under high iron-stress while those of FET4 gene increased under low iron stress. ZRC1 expression level increased up to three-fold of the reference strain under control conditions in M8FE grown only under high (15 mM) iron-stress. High ironstress resulted in a significant increase in CCC1 and COT1 gene expression levels in M8FE, similar to ZRC1.

Conclusions: Gene expression analysis results showed that FET3 and AFT1 genes are related to iron resistance and environmental iron ion levels. Gene expression level data imply that CCC1, responsible for vacuolar iron-transport, ZRC1, for vacuolar zinctransport, and COT1, for vacuolar cobalt transport which all may be associated with vacuolar iron transport under high levels of iron stress, and iron resistance.