Disruption of the cyclosporin synthetase gene of Tolypocladium niveum
1995
Weber, G. | Leitner, E. (Biochemie Ges.m.b.H., Kufstein-Schaftenau (Austria))
Cyclosporin A is a potent and clinically-important immunosuppressive drug (Sandimmun(R)). It is produced by the fungus Tolypocladium niveum. A transformation system for T. niveum ATCC34921 based on hygromycin selection was established. In order to obtain a T. niveum promoter, the cyclophilin gene was isolated using the Neurospora crassa gene as probe. A plasmid vector was constructed in which the promoter region of the T. niveum cyclophilin gene was fused to a bacterial hygromycin phosphotransferase gene. Protoplasts were transformed with this plasmid and hygromycin-resistant transformants were isolated. Using this transformation system, mutants of T. niveum with disrupted versions of the cyclosporin synthetase gene (simA) were engineered by DNA-mediated transformation. Disruption of the gene resulted in loss of the ability to produce cyclosporins.
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