Aa-Pri2, a single-copy gene from Agrocybe aegerita, specifically expressed during fruiting initiation, encodes a hydrophobin with a leucine-zipper domain.

The Aa-Pri2 gene, specifically expressed during basidiocarp differentiation of the mushroom Agrocybe aegerita, was cloned. Sequence analysis showed a 525-nt ORF interrupted by three introns (51, 48, 54 bp). One TATA box (-94), two CAAT boxes (-382, -398) and one CT-rich motif (-149) were present. The transcription start point was located by primer extension at position -60. The hydrophobic Aa-PRI2 protein (123 aa) possessed a putative signal peptide (aa1-aa18), eight cysteine residues characteristic of the hydrophobin proteins, and one putative leucine-zipper domain (aa50-aa71). Hybridization of the genomic DNA of several edible mushrooms with the Aa-Pri2 cDNA, showed a 2.7-kb DNA fragment highly similar to the Aa-Pri2 gene in the species Agrocybe chaxingu; sequences showing slight hybridization signals were detected in Pleurotus eryngii, Lentinula edodes and Agaricus bisporus.