Differential regulation of genes encoding manganese peroxidase (MnP) in the basidiomycete Ceriporiopsis subvermispora

Abstract

We previously identified and characterized three mnp genes coding for manganese peroxidase (MnP) in the white rot fungus Ceriporiopsis subvermispora. In this work, we assessed transcript levels of mnp genes in liquid cultures of this fungus grown under various conditions. In the absence of Mn(2+), mnp1 and mnp2 mRNA were detected by Northern hybridization, irrespective of the lack of extracellular MnP activity. Addition of Mn(2+) to the cultures led to a marked increase in both transcripts, the highest titers being observed at 10 micro M Mn(2+). mnp1 mRNA was not detected at Mn(2+ )concentrations above 80 micro M, whereas mnp2 mRNA was still observed at 320 micro M Mn(2+). Differential regulation of these genes was confirmed by the addition of Cu(2+), Zn(2+), Ag(+) and Cd(2+). These metal ions dramatically elevated both transcripts and also allowed the detection of the mnp3 transcript. In most cases, the increase in mRNA levels was partially abolished by the simultaneous presence of Mn(2+), although the latter was strictly required to detect extracellular MnP activity. However, the lignin-related compound syringic acid specifically increased the mnp1 transcript, although only in the absence of Mn(2+). These results indicate that there is no clear correlation between mnp mRNA levels and MnP activity. In addition, they strongly suggest that Mn(2+) plays a post-transcriptional role which is essential for the presence of active MnP in the extracellular fluid.

Saline-Dependent Regulation of Manganese Peroxidase Genes in the Hypersaline-Tolerant White Rot Fungus Phlebia sp. Strain MG-60

“…In several fungi, a sufficient amount of Mn 2ϩ in the medium is required for MnP expression at the mRNA level (19). Differential regulation of mnp genes by manganese in Pleurotus ostreatus (4), C. subvermispora (18,32), and T. versicolor (6, 10, 12) was previously described. Addi- FIG.…”

The copper-dependent ACE1 transcription factor activates the transcription of the mco1 gene from the basidiomycete Phanerochaete chrysosporium

“…After centrifugation (15 min at 14 000 r.p.m. ), the aqueous phase was phenol-extracted in a clean tube and the RNA was obtained as described by Manubens et al (2003). Ten micrograms of total RNA was fractionated by electrophoresis in a formaldehyde-agarose gel (1.2 % w/v) and RNA integrity was verified by ethidium-bromide staining.…”

Cloning and characterization of the genes encoding the high-affinity iron-uptake protein complex Fet3/Ftr1 in the basidiomycete Phanerochaete chrysosporium

“…After 6 days of growth, the mycelium was separated from the culture fluid by filtration through Miracloth (Calbiochem) and immediately frozen in liquid nitrogen. The frozen mycelium was ground to a powder in a mortar containing liquid nitrogen, and total RNA was extracted as described by Manubens et al (2003).…”

“…For Northern-blot hybridization studies, 10 mg total RNA was fractionated by electrophoresis in a formaldehyde-agarose gel (1.2 %, w/v) and analysed for the presence of mRNAs encoding Pc-fet3 and Pc-ftr1 as described by Manubens et al (2003). The cDNA probe for Pc-fet3 was prepared with the oligonucleotide primers 59-GAACATGGCGAATGCAGA-39 (direct) and 59-ATGCGGTCGGCACTCGCCC-39 (reverse), whereas the probe for Pc-ftr1 was obtained with the same primers as used for the isolation of its complete cDNA.…”