Laccases are oxidoreductase enzymes involved in the oxidation of various phenolic compounds. They may play a role in the biodegradation of lignin and in the dechlorination of chlorophenols. The cDNAs encoding laccase LccI and a putative laccase LccIV and the gene for LccI from the white-rot basidiomycete Trametes versicolor were cloned, sequenced and characterized. The genomic DNA of lccI consists of 2128 bp, with the coding region interrupted by 10 introns; the cDNA consists of a 1560 bp open reading frame (ORF). The cDNA of the putative lccIV gene consists of a 1581 bp ORF, with a 794 bp 5' untranslated region. The size of the major transcript for both lccI and lccIV is approximately 2.3 kb. Transcription of lccIV was induced by 2,5-dimethylaniline, whereas the opposite effect was observed for lccI. Laccases I and IV contain highly conserved histidinyl and cysteinyl residues, believed to be involved in binding copper, and share extensive sequence similarity with other laccases produced by both ligninolytic and non-ligninolytic fungi.