Metal-activated laccase promoters

Production of laccase isoenzymes POXC and POXAlb in the white rot basidiomycete Pleurotus ostreatus is induced by copper at the level of gene transcription, poxc and poxalb promoter regions, extending 200 nucleotides upstream of the ATG, contain multiple putative metal responsive elements (MREs) similar to the core MRE consensus sequence identified in the promoters of metallothionein genes from higher eukaryotes. It has been demonstrated that one or more proteins specifically bind poxalb and poxc promoter regions when the fungus is grown in the presence of added copper. On the other hand, some factors interact with the analysed poxc promoter region also when the fungus is grown without copper addition. Furthermore, the presence of copper is needed to form specific complexes.