The second cysteine-rich domain of Mac1p is a potent transactivator that modulates DNA binding efficiency and functionality of the protein

Mac1p is a Saccharomyces cerevisiae DNA binding transcription factor that a ctivates genes involved in copper uptake. A copper-induced N-C-terminal int ramolecular interaction and copper-independent homodimerization affect its function. Here, we present a functional analysis of Mac1p deletion derivati ves that attributes new roles to the second cysteine-rich (REPII) domain of the protein. This domain exhibits the copper-responsive potent transactiva tion function when assayed independently and, in the context of the entire protein, modulates the efficiency of Mac1p binding to DNA, The efficiency o f binding to both copper-response promoter elements can determine the in vi vo functionality of Mac1p independent of homodimerization, (C) 2001 Federat ion of European Biochemical Societies. Published by Elsevier Science B.V. A ll rights reserved.