Candida albicans ferric reductase FRP1 is regulated by direct interaction with Rim101p transcription factor

The opportunistic pathogen Candida albicans develops different systems to acquire essential nutrients such as iron. The Rim101 pathway controls gene expression to adapt to different environments through transcription factor Rim101p. Ferric reductase genes are important for iron acquisition, but further work should be carried out to show about how ferric reductase genes are regulated. In this study we demonstrate that ferric reductase FRP1 expression is upregulated by alkaline pH and iron-limited conditions. Moreover, promoter deletion identified that the upregulated elements lie in -822 to 437 and 263 to -124 and the downregulated elements in -437 to -263 using a beta-galactosidase reporter system. Using electrophoretic mobility shift assay we also found that Rim101p can bind directly with two putative 5'-CCAAGAA-3' sites at the -157 and -629 sites. Interestingly, site-specific mutations show that only the -629 site, not the -157 site, plays an important role in FRP1 expression under iron-limited conditions.