Expression of two closely linked hydrophobin genes of Coprinus cinereus is monokaryon-specific and down-regulated by the oid-1 mutation

Abstract

A protein with characteristic properties of a fungal hydrophobin (CoH1) was isolated from the monokaryotic stage of the basidiomycete Coprinus cinereus. A cosmid clone containing the corresponding gene (coH1) was identified using a cDNA probe derived by RT-PCR. Hybridization and sequence analysis identified a second gene, coH2, just 4.1 kb downstream of coH1 encoding a hydrophobin (CoH2) with 64% sequence identity. Both coH1 and coH2 are subject to developmental regulation. They are expressed in vegetative monokaryotic cells but not in the asexual oidia produced on the surface of monokaryons. Transcripts of the genes were barely detected in dikaryotic mycelium and were absent from fruit bodies. Loss of aerial growth due to a mutation known as oid-1 was correlated with lack of both hydrophobins.