Saccharomyces cerevisiae CUP1 metallothionein promoter
Copper-inducible promoter of the S. cerevisiae CUP1 copper metallothionein gene. Transcription is activated by the Ace1 (Cup2) transcription factor in response to Cu2+. A 431-bp fragment upstream of the translation start confers copper-inducible expression on an E. coli galactokinase (galK) reporter in yeast (Butt et al. 1984).
Origin: Saccharomyces cerevisiae
Characteristics
Induction is specific to copper. Zinc, cadmium and gold did not induce galactokinase from a CUP1 promoter-galK fusion. On a low-copy plasmid, CuSO4 raised galactokinase expression about 50-fold, with induction at 20, 100 and 500 uM and the maximum at 100 uM. CUP1 mRNA rose about 50-fold on 0.5 mM CuSO4 in cells carrying a high-copy plasmid (Butt et al. 1984). Activation requires binding of the copper-activated Ace1/Cup2 factor to upstream elements, and expression can be tuned further by the ACE1 gene copy number.
Applications: Copper-inducible expression of heterologous genes and reporters in S. cerevisiae, shown with an E. coli galK reporter on a low-copy plasmid (Butt et al. 1984), including expression systems where dose-adjustable chemical induction is preferred over an all-or-nothing switch.
Limitations: Requires exogenous Cu2+ to induce, and zinc, cadmium or gold do not substitute (Butt et al. 1984). Among 0, 20, 100 and 500 uM CuSO4 the galK reporter activity was maximal at 100 uM, so raising copper further is not a way to raise expression.
Sequence
References
- Butt et al. (1984). Copper metallothionein of yeast, structure of the gene, and regulation of expression. PNAS - Butt 1984 CUP1 Promoter