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

Abstract

Lignin peroxidases (LIPs) and manganesedependent peroxidases (MNPs) are major components of the -ignin-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 proffles 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.The white-rot basidiomycete Phanerochaete chrysosporium has been the focus of intense worldwide research from the standpoint of lignin biodegradation and bioremediation of environmental pollutants (for review, see refs.

Reactive Oxygen Species and Induction of Lignin Peroxidase in Phanerochaete chrysosporium

“…Boominathan and Reddy (7) suggested that transcription from genes encoding certain LIP enzymes is controlled by cAMP levels, a starvation signal. We found that intracellular cAMP levels responded to starvation conditions and that similar cAMP levels occurred with or without oxygenation.…”

“…Liquid cultures of P. chrysosporium must be starved (nitrogen or carbon depletion) and exposed to a pure O 2 atmosphere to trigger LIP expression (4,11,26). Boominathan and Reddy (7) showed that transcription of genes encoding some LIP enzymes is controlled by cyclic AMP (cAMP) levels.…”

The Effect of Aeration upon the Secondary Metabolism of Microorganisms

“…(1990) showed that this enzyme was detectable only in cells grown in the presence of MO and that its induction was blocked in the presence of transcriptional inhibitors, suggesting a role for Mn2+ as a transcriptional regulator as well as a substrate. The regulation of MnP and lignin peroxidase is believed to be mediated by cAMP since changes in intracellular levels of this compound resulted in the differential regulation of these two enzymes (Boominathan and Reddy, 1992). The lack of LiP activity in cultures with high concentrations of Me' could be due to increased levels of phosphodiesterase, which degrades cAMP and is stimulated by Mn2+.…”

Elevation of Intracellular cAMP Levels by Dominant Active Heterotrimeric G Protein Alpha SubunitsScGP-AandScGP-Cin Homobasidiomycete,Schizophyllum commune

“…Fax: +81-24-593-2155; E-mail: yamagisi@affrc.go.jp Abbreviations: RAS, Schizophyllum RAS gene; ScGP-A, Schizophyllum commune G protein alpha subunit A; ScGP-C, Schizophyllum commune G protein alpha subunit C and bioremediation. [13][14][15] Although the mechanism regulating the cAMP level in homobasidiomycete has not yet been explained, the putative components that are supposed to activate adenylyl cyclase have been reported. The homobasidiomycete RAS gene was first identified from Lentinus edodes (LeRas), which could functionally replace its homolog genes (ScRAS1 and ScRAS2) in S. cerevisiae.…”