%0 Journal Article %A Soden, Declan M. %A Dobson, Alan D. W. %T Differential regulation of laccase gene expression in Pleurotus sajor-cajuThe GenBank accession numbers for the sequences determined in this work are AF297525–AF297528. %D 2001 %J Microbiology, %V 147 %N 7 %P 1755-1763 %@ 1465-2080 %R https://doi.org/10.1099/00221287-147-7-1755 %K LNC, low nitrogen and carbon %K HN, high nitrogen %K gDNA, genomic DNA %K ligninolytic enzymes %K white-rot fungus %K HBT, 1-hydroxybenzotriazole %K EF, extracellular fluid %K XYL, 2,5-xylidine %K transcriptional regulation %K HC, high carbon %K FA, ferulic acid %K polyphenol oxidases %I Microbiology Society, %X Four laccase isozyme genes, Psc lac1, 2, 3 and 4 have been cloned from the edible mushroom, Pleurotus sajor-caju. The genes display a high degree of homology with other basidiomycete laccases (55–99%) at the amino acid level. Of the laccase genes isolated, Psc lac1 and 4 displayed the highest degree of similarity (85% at the amino acid level), while Psc lac3 showed the highest degree of divergence, exhibiting only 52–57% amino acid similarity to the other Pl. sajor-caju laccase gene sequences. Laccase activity in Pl. sajor-caju is affected by nutrient nitrogen and carbon, and by the addition of copper and manganese to the growth medium. In addition, 2,5-xylidine, ferulic acid, veratric acid and 1-hydroxybenzotriazole induced laccase activity in the fungus. Induction of individual laccase isozyme genes by carbon, nitrogen, copper, manganese and the two aromatic compounds, 2,5-xylidine and ferulic acid, occured at the level of gene transcription. While Psc lac3 transcript levels appeared to be constitutively expressed, transcript levels for the other laccase isozyme genes, lac1, 2 and 4, were differentially regulated under the conditions tested. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-147-7-1755