A chemical potentiator of copper‐accumulation used to investigate the iron‐regulons of S accharomyces cerevisiae

• Published in: Molecular microbiology Vol. 93; no. 2; pp. 317 - 330
• Main Authors: Foster, Andrew W., Dainty, Samantha J., Patterson, Carl J., Pohl, Ehmke, Blackburn, Hannah, Wilson, Clare, Hess, Corinna R., Rutherford, Julian C., Quaranta, Laura, Corran, Andy, Robinson, Nigel J.
• Format: Journal Article
• Language: English
• Published: 01.07.2014
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/mmi.12661

Summary The extreme resistance of S accharomyces cerevisiae to copper is overcome by 2‐(6‐benzyl‐2‐pyridyl)quinazoline ( BPQ ), providing a chemical‐biology tool which has been exploited in two lines of discovery. First, BPQ is shown to form a red ( BPQ ) 2 Cu(I) complex and promote Ctr 1‐independent copper‐accumulation in whole cells and in mitochondria isolated from treated cells. Multiple phenotypes, including loss of aconitase activity, are consistent with copper‐ BPQ mediated damage to mitochondrial iron–sulphur clusters. Thus, a biochemical basis of copper‐toxicity in S . cerevisiae is analogous to other organisms. Second, iron regulons controlled by Aft 1/2, Cth 2 and Yap 5 that respond to mitochondrial iron–sulphur cluster status are modulated by copper‐ BPQ causing iron hyper‐accumulation via upregulated iron‐import. Comparison of copper‐ BPQ treated, untreated and copper‐only treated wild‐type and fra2 Δ by RNA ‐seq has uncovered a new candidate Aft 1 target‐gene ( LSO1 ) and paralogous non‐target ( LSO2 ), plus nine putative Cth 2 target‐transcripts. Two lines of evidence confirm that Fra 2 dominates basal repression of the Aft 1/2 regulons in iron‐replete cultures. Fra 2‐independent control of these regulons is also observed but CTH2 itself appears to be atypically Fra 2‐dependent. However, control of Cth 2‐target transcripts which is independent of CTH2 transcript abundance or of Fra 2, is also quantified. Use of copper‐ BPQ supports a substantial contribution of metabolite repression to iron‐regulation.