Isolation of transcripts preferentially expressed during fruit body primordia differentiation in the basidiomycete Agrocybe aegerita.

An Agrocybe aegerita cDNA library, constructed from fruit body primordia poly(A)+ RNAs, was screened by differential colony hybridization. Clones which preferentially hybridized to poly(A)+ RNA sequences from fruit body primordia, versus poly(A)+ RNAs from mycelium, were isolated. Eight of these clones (EMAa-1 to EMAa-8) encoded eight different poly(A)+ RNAs which were demonstrated to be undetectable in the four stages preceding primordia formation and to be concomitantly accumulated when primordia differentiate, suggesting that EMAa gene products are closely involved in the morphogenesis of primordia. The eight EMAa cDNAs hybridize to at least seven unique regions distributed randomly in the A. aegerita genome. The expression of two EMAa cDNA sequences in E. coli led to the isolation of their gene products as fusion proteins.