A REPORTER GENE CONSTRUCT FOR STUDYING THE REGULATION OF MANGANESE PEROXIDASE GENE-EXPRESSION

The orotidylate decarboxylase (ODase) gene (ura1) from Schizophyllum c ommune was utilized as a reporter for studying Mn regulation of the ma nganese peroxidase (MnP) gene (mnp) from the lignin-degrading basidiom ycete Phanerochaete chrysosporium. A 1,500-bp fragment of the mnp1 pro moter was fused upstream of the coding region of the ODase gene in a p lasmid (pAMO) containing the S. commune ade5 gene as a selectable mark er. pAMO was used to transform a P. chrysosporium ade1 ura11 mutant la cking endogenous ODase activity. When the P. chrysosporium transforman t was grown in nitrogen-limited, Mn(II)-sufficient cultures, ODase act ivity was detected only during secondary metabolic growth and the patt ern 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 maxima l activity at 30 h. Growth in high-nitrogen-concentration medium suppr essed the induction of both the ODase and endogenous MnP. These result s indicate that this promoter-reporter construct can be used to study the regulation of the mnp gene.