ISOLATION AND CHARACTERIZATION OF A LACCASE GENE FROM PODOSPORA-ANSERINA

The genome of the filamentous ascomycete Podospora anserina contains a t least four non-adjacent regions that are homologous to the laccase g ene of Neurospora crassa. One of these regions contains a gene (lac2) encoding a protein that displays 62% identity with the N. crassa lacca se. In shaken cultures, lac2 mRNA is present at low basal levels throu ghout the growth phase but increases at least 20-fold at the beginning of the autolytic phase and decreases again thereafter. Addition of ar omatic xenobiotics (guaiacol, hydroquinone, benzoquinone) to the mediu m during the growth phase results in a rapid, drastic and temporary in crease in the abundance of lac2 mRNA. The promoter region of lac2 cont ains two sequences which display complete homology with the eukaryotic Xenobiotic Responsive Element and two sequences homologous to the euk aryotic Antioxidant Responsive Element. The identity and function of t he laccase encoded by lac2 are discussed.