Changes in complex RNA during fruit-body initiation in the fungus Schizophyllum commune

Total RNA was isolated from 4-day surface cultures of two monokaryotic strains (vegetative mycelium) and a resultant dikaryotic strain bearing fruit-body initials (fruiting mycelium) of the basidiomycete Schizophyllum commune. Single-copy DNA (scDNA) and complementary DNA (cDNA) hybridizations with these RNAs showed that both mycelial types expressed 10, 000 to 13, 000 different RNA sequences of average size. scDNA combination-hybridization experiments did not reveal differences between the RNA populations. However, cDNA cross-hybridization experiments indicated that about 5% of the complex RNA mass present in fruiting mycelium was absent in vegetative mycelium. Homologous and heterologous hybridization of total RNA with cDNA probes corresponding to more and less frequently occurring RNA sequences demonstrated that the fruiting mycelium contained about 35 specific abundant RNAs. Comparison of cell-free translation products of total RNA showed a similar difference between the abundant RNA species in vegetative and fruiting mycelium. Of about 400 polypeptides detected after two-dimensional gel electrophoresis, 18 were encoded exclusively by RNA from the fruiting dikaryon