title: Combination strategy to increase cyclosporin A productivity by Tolypocladium niveum using random mutagenesis and protoplast transformation.
abstract: The cyclic undecapeptide cyclosporin A (CyA), one of the most valuable immunosuppressive drugs, is produced nonribosomally by a multifunctional cyclosporin synthetase enzyme complex by the filamentous fungus Tolypocladium niveum. To increase CyA productivity by wild-type T. niveum (ATCC 34921), random mutagenesis was first performed using an antifungal agar-plug colony assay (APCA) selection approach. This generated a mutant strain producing more than 9-fold greater CyA than the wild-type strain. Additionally, a foreign bacterial gene, Vitreoscilla hemoglobin gene (VHb), was transformed via protoplast regeneration and its transcription was confirmed by RT-PCR in the UV-irradiated mutant cell. This led to an additional 33.5% increase of CyA production. Although most protoplastregenerated T. niveum transformants tend to lose CyA productivity, the optimized combination of random mutagenesis and protoplast transformation described here should be an efficient strategy to generate a commercially valuable, yet metabolite low-producing, fungal species, such as CyA producing T. niveum.
authors.affiliation: Department of Biological Engineering, Inha University, Incheon 402-751, Korea.
authors.forename: Mi-Jin
authors.initials: MJ
authors.lastname: Lee
authors.forename: Cac Thi Phung
authors.initials: CT
authors.lastname: Duong
authors.forename: Kyuboem
authors.initials: K
authors.lastname: Han
authors.forename: Eung-Soo
authors.initials: ES
authors.lastname: Kim
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D016572:Cyclosporine / Q000378:metabolism*; D005798:Genes, Bacterial; D006999:Hypocreales / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D016296:Mutagenesis; D011523:Protoplasts / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D054793:Truncated Hemoglobins / Q000235:genetics; D020589:Vitreoscilla / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D054793:Truncated Hemoglobins; C082613:hemoglobin protein, Vitreoscilla; D016572:Cyclosporine