The Sc7/Sc14 gene family of Schizophyllum commune codes for extracellular proteins specifically expressed during fruit-body formation

Abstract

The Sc7 and Sc14 genes are specifically expressed in the dikaryon of the basidiomycete fungus Schizophyllum commune during fruiting. These genes are closely linked (within 6 kb) and highly similar in gene structure and nucleotide sequence (70% identical nucleotides in their coding regions). The encoded proteins (204 and 214 amino acids, respectively) have 87% similarity in amino acids (56% of the amino acids are identical). They contain putative signal sequences for secretion, are rich in aromatic amino acids which are generally located at similar positions, and they are generally hydrophilic. Inspection of databanks showed similarities with pathogenesis-related proteins (PR1) from plants, testis-specific proteins from mammals and venom allergen proteins from insects. An antibody raised against a Sc7 fusion protein showed the presence of the Sc7 protein in the culture medium and in the fruit bodies where it is apparently loosely associated with hyphal walls.