ABSTRACT
Restriction enzyme analysis was used to evaluate genomic DNA methylation patterns in two different life cycle stages of the button mushroom Agaricus bisporus. Our investigation reveals that some degree of 5-methylcytosine occurs in this fungus. Furthermore, methylation may be partially or fully specific for the internal cytosine of the CCGG recognition sequence. Evidence for 6-methyladenosine, 5-hydroxymethylcytosine, and 4-methylcytosine was not found. Methylation of cytosine at C-X-G sequences, common in higher plants, was not detected in A. bisporus genomic DNA. Cleavage of sporophore and mycelial DNA by a wide range of Type II endonucleases gave no evidence of developmental differences in methylation.