Promoter-tagged restriction enzyme-mediated insertion (PT-REMI) mutagenesis in Aspergillus niger

Promoter-tagged restriction enzyme-mediated insertion (PT-REMI) mutagenesis was performed in the fungus Aspergillus niger, using a plasmid containing a strong transcriptional promoter. Two DNA-tagged mutants were analyzed in detail. A white-spored mutant was shown to contain a plasmid insertion that disrupted a gene that shows a high degree of homology to the polyketide sy nthase gene wA of A. nidulans. A morphological mutant was shown to contain a plasmid insertion in the 5' upstream region of a gene that strongly resem bles COX5, which encodes the cytochrome c oxidase subunit V. Insertion of t he plasmid resulted in enhanced expression of the COX5 RNA, demonstrating t hat the combination of REMI with a promoter-containing insert can be used t o activate gene transcription.