A gene, Le.paa, encoding a regulatory subunit A (PR65) homologue of protein phosphatase 2A was isolated from the basidiomycete mushroom Lentinus edodes. The deduced Le.paa gene product (Le.PR65) had the highest sequence similarity to the Schizosaccharomyces pombe PR65 protein (54.1% similarity). The Le.paa gene was shown to be transcribed more actively during the late stages of fruiting development of the fungus. Gill tissue in which basidiospores are formed contained abundant Le.paa transcript as compared with gill-depleted pileus and stipe.