An aureobasidin A resistance gene isolated from Aspergillus is a homolog of yeast AUR1, a gene responsible for inositol phosphorylceramide (IPC) synthase activity

The AURI gene of Saccharomyces cerevisiae, mutations in which confer resist ance to the antibiotic aureobasidin A, is necessary for inositol phosphoryl -ceramide (IPC) synthase activity. We report the molecular cloning and char acterization of the Aspergillus nidulans aurA gene, which is homologous to AURI. A single point mutation in the nul A gene of A. nidulans confers a hi gh level of resistance to aureobasidin A. The A. nidulans aurA gene was use d to identify its homologs in other Aspergillus species, including A. fumig atus, A. niger, and A. oryzae. The deduced amino acid sequence of an aurA h omolog from the pathogenic fungus A. fumigatus showed 87% identity to that of A. nidulans. The AurA proteins of A. nidulans and A. fumigatus shared co mmon characteristics in primary structure, including sequence, hydropathy p rofile, and. N-glycosylation sites, with their S. cerevisiae, Schizosacchar omyces pombe, and Candida albicans counterparts. These results suggest that the aureobasidin resistance gene is conserved evolutionarily in various fu ngi.