Regulation of metallothionein genes by the ACE1 and AMT1 transcription factors.
The AMT1 metalloregulatory trans-acting factor from Candida glabrata was found to functionally mimic the ACE1 metalloregulatory trans-acting factor from Saccharomyces cerevisiae in the copper-induced expression of the chromosomal S. cerevisiae metallothionein gene. Plasmid constructs with promoters of various metal-inducible genes fused to the bacterial beta-galactosidase (lacZ) reporter gene were used in S. cerevisiae to evaluate the roles of ACE1 and AMT1 in mediating metal-stimulated expression. Promoters from the S. cerevisiae CUP1 gene and Cu,Zn-superoxide dismutase (SOD1) and from the C. glabrata MT genes MTI, MTIIa, and MTIIb were used. The ACE1 factor was effective in the metalloregulation of the two S. cerevisiae promoters, CUP1 and SOD1, but of only one C. glabrata promoter, MTI. AMT1 was found to be effective in the metalloregulation of all three C. glabrata MT promoters and the two S. cerevisiae promoters tested. The regulation mediated by both ACE1 and AMT1 was copper-dependent and copper-specific. Episomally expressed SWI5, a distinct trans-acting factor of S. cerevisiae, enhanced only the basal expression from promoters. The SWI5 enhancement was not metal dependent. In conclusion, AMT1 and ACE1 are functionally homologous in metal-specific regulation, AMT1 appears to be more promiscuous than ACE1 in this function.
Department of Biochemistry, University of Utah Medical Center, Salt Lake City 84132.
J L
JL
Thorvaldsen
A K
AK
Sewell
C L
CL
McCowen
D R
DR
Winge
D002175:Candida / Q000235:genetics; D003001:Cloning, Molecular; D003300:Copper / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D007700:Kinetics; D008668:Metallothionein / Q000235:genetics*; D008670:Metals / Q000494:pharmacology; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D013482:Superoxide Dismutase / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism*; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
C060256:CUP2 protein, S cerevisiae; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D008670:Metals; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C069807:AMT1 protein, Candida glabrate; D003300:Copper; D008668:Metallothionein; D013482:Superoxide Dismutase; D001616:beta-Galactosidase