title: Controlled expression and purification of human immune interferon from high-cell-density fermentations of Saccharomyces cerevisiae.
abstract: Conditions for high-cell-density fermentations of Saccharomyces cerevisiae strains producing recombinant-DNA-derived proteins were established. Strains producing human immune interferon (IFN-gamma) from the constitutive PGK promoter failed to grow to high cell densities and exhibited low plasmid stability. Regulated expression of IFN-gamma was obtained in similar strains by employing a hybrid yeast GPD promoter that was subject to carbon source regulation due to the presence of regulatory DNA sequences from the yeast GAL 1,10 intergenic region. IFN-gamma expression programmed by this vector was low during growth on glucose and was induced by galactose. Previously defined fermentation conditions employing glucose as a carbon source were applied to this strain, resulting in high ceil densities with higher plasmid stability. Various methods of galactose induction of IFN-gamma expression in high-cell-density fermentations were investigated. Optimal conditions resulted in a 2000-fold induction and production of 2 g IFN-gamma/L fermentation culture.
authors.affiliation: Amgen, 1900 Oak Terrace Lane, Thousand Oaks, California 91320.
authors.forename: J C
authors.initials: JC
authors.lastname: Fieschko
authors.forename: K M
authors.initials: KM
authors.lastname: Egan
authors.forename: T
authors.initials: T
authors.lastname: Ritch
authors.forename: R A
authors.initials: RA
authors.lastname: Koski
authors.forename: M
authors.initials: M
authors.lastname: Jones
authors.forename: G A
authors.initials: GA
authors.lastname: Bitter