Iron regulation of triosephosphate isomerase transcript stability in the yeast Saccharomyces cerevisiae

By differential hybridization we have identified cDNA clones that are derived from iron-regulated genes in Saccharomyces cerevisiae. Sequencing of seven cDNA clones revealed that five clones correspond to TPI1 encoding triosephosphate isomerase (Tpi1p) and one corresponds to TDH3 encoding glyceraldehyde-3-phosphate dehydrogenase (Tdh3p). During iron-limited growth mRNA levels for Tpi1p and Tdh3p were at least 3-fold lower than during iron-saturated growth; as shown with a hem1 mutant strain this regulation does not require haem synthesis. mRNA half-lives of TPI1 (TDH3) were 11.5 min (18 min) in low-iron medium and 30 min (32.5 min) in high-iron medium, indicating iron-regulation of transcript half-lives; the stabilities of the ACT1 and PDC1 transcripts were not influenced by iron. Increased glycerol production during growth in low-iron, as compared to high-iron medium, is consistent with a modification of the glycolytic flux during iron-limited growth in S. cerevisiae.