Characterization of the AN6448 cluster in Aspergillus nidulans

With the aim of mapping the polyketome of A. nidulans we have made a library of strains, which individually overexpress PKS genes from an ectopic locus. A screen of this collection on different media demonstrated that AN6448 leads to production of 3-MOA. An inspection of the DNA sequence surrounding this gene uncovered a putative gene cluster including a gene, AN6446, with homology to transcription factors.

Based on this observation, we decided to overexpress AN6446. A qRT-PCR analysis of this strain was used to delineate the borders of the gene cluster as well as to stimulate formation of cichorine and a number of new products, from the gene cluster. Subsequent deletion of all genes allowed several steps in the biosynthetic pathway in this cluster to be clarified.