A gene encoding a hydrophobin, fvh1, is specifically expressed after the induction of fruiting in the edible mushroom Flammulina velutipes

A cDNA clone of the gene fvh1 was previously isolated from a preprimordial cDNA library made from the basidiomycete Flammulina velutipes. Sequence ana lysis showed that fvh1 encoded for a hydrophobin, a small fungal protein us ually secreted by filamentous fungi. FVH1 had a highly conserved arrangemen t of eight cysteine residues, a putative N-terminal signal sequence and a h ydropathy pattern characteristic of class I hydrophobin. A genomic fvh1 clo ne was isolated from a F. velutipes genomic DNA library and sequenced. Seve ral putative promoter elements and three small introns of fvh1 were identif ied in this clone. Southern blot analysis of genomic DNA showed that fvh1 w as a single copy gene. Northern analysis indicated that fvh1 was specifical ly and abundantly expressed in mycelia after the induction of fruiting and during fruit body initiation. It was not expressed in mycelia before the in duction of fruiting or in mature fruit bodies.