Improved transformation frequency and heterologous promoter recognition in Aspergillus niger
1990
Mohr, G. | Esser, K.
Wild-type strains of Aspergillus niger were transformed with integrative vectors. The number of stable transformants varied from approximately 20-30/ microgram up to 17,000/microgram using acetamide and hygromycin B selection, respectively. The introduction of deletions or 5' and 3' non-coding regions of the acetamidase gene (amdS+) revealed that these sequences influenced the number of transformants. The molecular characterization of A. niger transformants revealed that several copies of the vectors were tandemly integrated into the nuclear DNA. These oligomers were stably inherited, even after 100 days of growth on non-selective medium. The expression of the vector-encoded genes was confirmed by evidence from the mRNAs and corresponding proteins encoded by the selectable marker genes.
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