MANGANESE REGULATES EXPRESSION OF MANGANESE PEROXIDASE BY PHANEROCHAETE-CHRYSOSPORIUM

The appearance of manganese peroxidase (MnP) activity in nitrogen-limited cultures of Phanerochaete chrysosporium is dependent on the presence of manganese. Cultures grown in the absence of MN developed normally and produced normal levels of the secondary metabolite veratryl alcohol but produced no MnP activity. Immunoblot analysis indicated that appearance of MnP protein in the extracellular medium was also dependent on the presence of Mn. Intracellular MnP protein was detectable only in cells grown in the presence of Mn. MnP mRNA was detected by Northern (RNA) blot analysis only in cells grown in the presence of Mn. If Mn was added to 4-day-old nitrogen-limited Mn-deficient cultures, extracellular MnP activity appeared after 6 h reached a maximum after 18 h. Both actinomycin D and cycloheximide inhibited the induction of MnP activity by Mn. These results indicate that Mn, the substrate of the enzyme, is involved in the transcriptional regulation of the MnP gene.