FRUITING GENES OF SCHIZOPHYLLUM-COMMUNE ARE TRANSCRIPTIONALLY REGULATED

Fruiting genes in Schizophyllum commune are controlled by the mating-type genes and other regulatory genes. To examine whether differential accumulation of mRNAs for these fruiting genes is caused by transcriptional regulation, run-on transcription assaYs were performed with nuclei isolated from cultures differing in expression of these genes. It could be shown that accumulation of mRNAs followed enhanced transcription of most of the fruiting genes. Transcription continued during subsequent decrease of these mRNAs. In young not-yet-fruiting dikaryons and non-fruiting monokaryons the fruiting genes appeared to be transcribed at a low basal level. The GPD gene was used a control in these experiments and was transcribed at all stages

Double-stranded RNA mycoviruses in mycelium of Pleurotus ostreatus

Mycelium of Pleurotus ostreatus var. florida with a decreased growth rate contained seven double-stranded RNA segments and isometrical virus particles with diameters of 24 and 30 nm. Mycelium with a normal growth rate lacked dsRNA. Protoclones from virus-containing mycelium contained one to seven of these dsRNA segments in varying concentrations. The exact correlation between slow growth and the presence of dsRNA molecules could not be established. Infection of virus-free protoplasts with PEG-precipitated virus particles resulted in mycelium that stably maintained the 2.4 kbp dsRNA