Chemical potentiator of copper-accumulation and -toxicity: Probing iron- regulons of Saccharomyces cerevisiae

RNA-seq was used to assess mRNA transcript abundance in wild type and fra2? S. cerevisiae (BY4741) cells treated with 2-(6-benzyl-2-pyridyl)quinazoline (BPQ) and CuSO4. BPQ potentiates copper toxicity and in yeast, in common with other organisms, a major cause of copper toxicity is damage of iron-sulphur clusters. Iron sensing within yeast relies on mitochondrial iron-sulphur cluster biosynthesis and therefore treatment with BPQ and copper can be used to mimic iron deficiency. Fra2 is known to be a key component of the iron sensing mechanism; however, this mechanism can operate, to an extent, independently of Fra2. BPQ (+CuSO4) treatment was used with the aim of probing the regulation of the iron regulon of S. cerevisiae and the role of Fra2 in the suppression of the low iron response. This study has uncovered nine new Cth2 target-transcripts, plus a new Aft1 target-gene and paralogous non-target. Fra2 dominates basal repression of the iron regulon in iron-replete cultures, however, Fra2-independent control of the iron regulon is also observed with CTH2 appearing to be atypically Fra2-dependent. Transcripts from untreated and CuSO4 treated cells were included as controls. Overall design: Three independent biological replicates were analysed for each condition (BPQ and CuSO4 treated wild type and fra2? cells, CuSO4 treated wild type and fra2? cells and untreated wild type and fra2? cells)

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Foster AW, Dainty SJ, Patterson CJ, Pohl E, Blackburn H, Wilson C, Hess CR, Rutherford JC, Quaranta L, Corran A, Robinson NJ