[Regulating promoter element of iron-dependent gene FRP1 in Candida albicans by site-directed mutation]

Microarray analysis revealed that the expression of ferric reductase (FRP1) can be regulated by the Riml01 protein. In order to find new transcriptional regulatory element in the promoter of FRP1, we analyzed the 1000 bp sequence upstream of ATG to find 2 potential Riml01p binding sites. We generated site-specific mutations in each of the two sites and fused these mutated promoters to LacZ. Then the promoter-LacZ fusion construct was recombinant into wild type and riml01-/- strains for beta-galactosidase assay. The results revealed that the FRP1 was up-regulated in alkaline pH and this was caused by iron starvation. The -650 site, not the -160 site, had an important role in FRP1 Riml01p-dependent expression. We conclude that Riml01p may interact with the -650 binding site of the promoter to regulate the FRP1 expression.