Functional characterization of the copper transcription factor AfMac1 from .

Although copper functions as a cofactor in many physiological processes, copper overload leads to harmful effects in living cells. Thus, copper homeostasis is tightly regulated. However, detailed copper metabolic pathways have not yet been identified in filamentous fungi. In this report, we investigated the copper transcription factor AfMac1 ( homolog) and identified its regulatory mechanism in AfMac1 has domains homologous to the DNA-binding and copper-binding domains of Mac1 from , and AfMac1 efficiently complemented Mac1 in Expression of resulted in up-regulation, and mutation of the DNA-binding domain of failed to activate expression in The deletion strain of failed to grow in copper-limited media, and its growth was restored by introducing We found that AfMac1 specifically bound to the promoter region of based on EMSA. The AfMac1-binding motif 5'-TGTGCTCA-3' was identified from the promoter region of , and the addition of mutant lacking the AfMac1-binding motif failed to up-regulate in Furthermore, deletion of significantly reduced strain virulence and activated conidial killing activity by neutrophils and macrophages. Taken together, these results suggest that AfMac1 is a copper transcription factor that regulates cellular copper homeostasis in .