Ferric reductase of Saccharomyces cerevisiae: molecular characterization, role in iron uptake, and transcriptional control by iron.

摘要: Abstract The principal iron uptake system of Saccharomyces cerevisiae utilizes a reductase activity that acts on ferric chelates external to the cell. The FRE1 gene product is required for this activity. deduced amino acid sequence protein exhibits hydrophobic regions compatible with transmembrane domains and has significant similarity plasma membrane cytochrome b558 (the X-CGD protein), critical component human phagocyte oxidoreductase, suggesting structural yeast reductase. mRNA levels are repressed by iron. Fusion 977 base pairs DNA upstream from translation start site an Escherichia coli lacZ reporter confers iron-dependent regulation expression beta-galactosidase in yeast. An 85-base-pair segment 5' noncoding contains RAP1 binding repeated sequence, TTTTTGCTCAYC; sufficient confer iron-repressible transcriptional heterologous downstream promoter elements.