cAMP-mediated differential regulation of lignin peroxidase and manganese-dependent peroxidase production in the white-rot basidiomycete Phanerochaete chrysosporium.

Lignin peroxidases (LIPs) and manganese-dependent peroxidases (MNPs) are major components of the lignin-degrading enzyme system of Phanerochaete chrysosporium and typically appear during secondary metabolism. The involvement of cAMP in the regulation of production of LIPs and MNPs was investigated in this study. Production of LIPs and MNPs was preceded by a sharp rise in intracellular cAMP concentration. Addition of atropine, theophylline, or histamine to cultures resulted in a drop in intracellular cAMP concentration and a concomitant inhibition of production of LIPs only or of both LIPs and MNPs, depending on the concentration of the inhibitor added. These results were independently confirmed by fast protein liquid chromatographic profiles of the LIPs and MNPs in the extracellular fluid of the inhibitor-treated and untreated control cultures. LIP production was generally more sensitive to the inhibitors than MNP production. Northern blot analyses showed that the inhibitors affect the production of LIPs and MNPs at the level of transcription. Furthermore, LIP and MNP gene expression appears to be differentially regulated depending on the intracellular concentration of cAMP. These results show that cAMP plays a key role in the regulation of production of LIPs and MNPs in P. chrysosporium.