The laccase multi-gene family in Coprinopsis cinerea has seventeen different members that divide into two distinct subfamilies

• DOI: 10.1007/s00294-006-0074-1
• Publication Date: 2006-04-28T09:43:59Z
• Authors: Sreedhar Kilaru; Patrik J. Hoegger; Ursula Kües
• Keywords: 0301 basic medicine; Base Sequence; Sequence Homology, Amino Acid; Genetic Speciation; Genes, Fungal; Laccase; Molecular Sequence Data; Introns; Protein Structure, Secondary; Coprinus; Evolution, Molecular; Fungal Proteins; Contig Mapping; 03 medical and health sciences; Amino Acid Substitution; Gene Duplication; Multigene Family; Consensus Sequence; Amino Acid Sequence; Codon; Alleles; Phylogeny

Seventeen non-allelic laccase genes and one gene footprint are present in the genome of Coprinopsis cinerea. Two gene subfamilies were defined by intron positions and similarity of deduced gene products, one with 15 members (lcc1-lcc15) and one with 2 members (lcc16, lcc17). The first subfamily divides in the phylogenetic tree of deduced proteins into smaller clusters that probably reflect recent gene duplication events. Different laccase genes diverged from each other both by frequent synonymous and non-synonymous codon changes. Mainly synonymous codon changes accumulate in alleles, with up to 12% total codon differences between given pairs of alleles. Overexpression of the 17 laccase genes under the control of a constitutive promoter identified nine active enzymes from subfamily 1. All of these showed laccase activities with DMP (2,6-dimethoxy phenol) as substrate but only eight of them also with ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)]. Lcc16 and Lcc17 share certain sequence features with ferroxidases but enzyme assays failed to show such activity. Lcc15 is expected to be non-functional in laccase activity due to an internal deletion of about 150 amino acids. Transcripts were obtained from all genes but splice junctions for three genes were not congruent with translation into a functional protein.