A homology-based PCR method was used to clone a cDNA encoding lanosterol synthase (LS) from Ganoderma lucidum (G. lucidum), which produces triterpenes. The cDNA of the LS (GenBank accession no. GQ169528) was found to contain an open reading frame (ORF) of 2,181 bp encoding a 726 amino acid polypeptide, whereas the LS genomic DNA sequence (GenBank accession no. GQ169529) consists of 2,924 bp. Functional complementation of G. lucidum LS (Gl-LS) in an erg7 yeast strain lacking LS activity demonstrated that the cloned cDNA encoded a functional LS. Analysis of the Gl-LS transcript profiles revealed a positive correlation between the pattern of LS gene expression and triterpenes content changes in G. lucidum during development. Up-regulation of expression of the Gl-LS gene by methyl jasmonate (MeJA) in the mycelia was also demonstrated by real-time RT-PCR. Up-regulation of the Gl-LS promoter activity by MeJA was also investigated.