A reporter gene construct for studying the regulation of manganese peroxidase gene expression

The orotidylate decarboxylase (ODase) gene (ura1) from Schizophyllum commune was utilized as a reporter for studying Mn regulation of the manganese peroxidase (MnP) gene (mnp) from the lignin-degrading basidiomycete Phanerochaete chrysosporium. A 1,500-bp fragment of the mnp1 promoter was fused upstream of the coding region of the ODase gene in a plasmid (pAMO) containing the S. commune ade5 gene as a selectable marker. pAMO was used to transform a P. chrysosporium ade1 ura11 mutant lacking endogenous ODase activity. When the P. chrysosporium transformant was grown in nitrogen-limited, Mn(II)-sufficient cultures, ODase activity was detected only during secondary metabolic growth and the pattern of ODase expression was similar to that of endogenous MnP. When Mn was added to 6-day-old nitrogen-limited, Mn-deficient cultures, both ODase activity and MnP activity were induced synchronously with maximal activity at 30 h. Growth in high-nitrogen-concentration medium suppressed the induction of both the ODase and endogenous MnP. These results indicate that this promoter-reporter construct can be used to study the regulation of the mnp gene.