Disease relevance of CUP2

• Using mobility shift, methylation interference, and DNase I and hydroxyl radical footprinting assays, we examined the interaction of wild-type and variant CUP2 proteins produced in Escherichia coli with the UASc [1].
• However, the toxicity of cisplatin in cells with a disrupted gene for ACE1, a factor that regulates transcription of the yeast gene for metallothionein, was also significantly reduced by treatment with copper [2].

High impact information on CUP2

• However, TAF17-depleted cells maintain Ace1-dependent activation, and they induce de novo activation by heat shock factor in a manner predominantly associated with the activator, not the core promoter [3].
• Here we report the identification of a nuclear protein from S. cerevisiae, MAC1, whose N-terminal region is highly similar to the copper and DNA binding domains of ACE1 and AMT1 [4].
• ACE1 and AMT1 are 'copper-fist' transcription factors which possess a conserved cysteine-rich copper binding domain required for DNA binding [4].
• The CUP2 gene product regulates the expression of the CUP1 gene, coding for yeast metallothionein [5].
• The functional importance of this DNA-protein interaction is demonstrated by the facts that (i) copper induction of SOD1 mRNA does not occur in a strain lacking ACE1 and (ii) it does not occur in a strain containing a genetically engineered SOD1 promoter that lacks a functional ACE1 binding site [6].

Biological context of CUP2

• We show that CUP2, which is on chromosome VII, codes for or controls the synthesis or activity of a protein which binds the upstream control region of the CUP1 gene on chromosome VIII [5].
• CUP2 mutant alleles from Cu-sensitive yeast strains have point mutations affecting the DNA-binding activity [7].
• We have isolated a gene, designated ACE2, which when present on a high-copy-number plasmid suppresses the copper-sensitive phenotype of an ace1-deletion strain [8].
• Induction requires the ACE1 gene product, which binds to specific sites in the promoter region of the CUP1 gene [8].
• In this study, we found that deleting the entire coding sequence of the ACE1 gene resulted in a decrease in basal-level transcription of CUP1 to low but detectable levels and conferred a copper-sensitive phenotype to the cells [8].

Anatomical context of CUP2

• The ability of a bifunctional ACE1-beta-galactosidase fusion protein to accumulate in yeast cell nuclei was consistent with the possibility that ACE1 plays a direct role in the regulation of copper-inducible transcription of the yeast metallothionein gene [9].

Associations of CUP2 with chemical compounds

• The CUP2 protein contains a cysteine-rich DNA-binding domain dependent on Cu+ and Ag+ ions which bind the cysteine residues and direct the refolding of the metal-free apoprotein [7].
• Using an ethyl methanesulfonate mutant of a yeast strain in which CUP1 and ACE1 were deleted, we isolated a gene, designated CUP9, which permits yeast cells to grow at high concentrations of environmental copper, most notably when lactate is the sole carbon source [10].
• In vivo dimethyl sulfate footprinting analysis of the CUP1 promoter demonstrated transient occupation of the metal response elements by Ace1p which paralleled CUP1 mRNA expression [11].
• The results are consistent with the N-terminal halves of AMT1 and ACE1 consisting of two independent submodules, one binding a single Zn(II) ion and the second binding the tetracopper cluster [12].
• Moreover, this inhibition appears to be a result of a direct interaction between Ace1 thiols and HNO and not a result of any chemistry associated with HNO-derived species [13].

Physical interactions of CUP2

• A single binding site for ACE1 is present in the SOD1 promoter region, as demonstrated by DNase I protection and methylation interference experiments, and is highly homologous to a high-affinity ACE1 binding site in the CUP1 promoter [6].

Regulatory relationships of CUP2

• These studies (i) demonstrate that the nutritional and toxic copper metalloregulatory transcription factors Mac1p and Ace1p must sense and respond to copper ions in a dynamic fashion to appropriately regulate copper ion homeostasis and (ii) establish the requirement for a wild-type Mac1p for survival in the presence of toxic copper levels [11].
• By contrast, transcription of CUP1 mediated by both Hsf1 and copper-activated transcription factor Ace1 was inducible after inactivating TFIIE [14].

Other interactions of CUP2

• Strains with a complete deletion of the ACE1 gene, the copper-dependent activator of CUP1 transcription, are hypersensitive to copper [15].

Analytical, diagnostic and therapeutic context of CUP2

• Considering the similarity of metal-thiolate ligation in Ace1 with other mammalian metalloproteins such as metallothionein, metal chaperones, and zinc-finger proteins, these results help to understand the biochemical interactions of NO with those mammalian metalloproteins [16].
• Similarly, in vivo cross-linking and chromatin immunoprecipitation assays demonstrate association of DmORC with both ACE3 and two other amplification control elements, AER-d and ACE1 [17].

References