title: Expression of secreted insulin-like growth factor-1 in Escherichia coli.
abstract: The synthesis, processing and secretion of insulin-like growth factor-1 (IGF-1 or somatomedin-C) fused to LamB and OmpF secretion leader sequences in Escherichia coli have been investigated. Expression and secretion of IGF-1 was achieved. The major portion of this secreted IGF-1 accumulated in the periplasmic space as insoluble aggregates. A small amount of IGF-1 was found folded in its native conformation in the medium. The lamB and ompF signal sequences were fused to the 5' coding sequence of IGF-1. Fusion of the lamB signal sequence directly to IGF-1 (lamB-IGF-1) resulted in accumulation of 16-20 micrograms/A550/ml of correctly processed IGF-1 in the periplasmic space. The processing efficiency of LamB-IGF-1 and OmpF-IGF-1 was enhanced in an E. coli strain bearing a prlA4 mutation. Amino acid sequence analysis of IGF-1 secreted into the periplasm and exported into the medium confirmed the precise removal of the LamB or OmpF signal sequence. IGF-1 synthesized in E. coli was demonstrated to be active in a cell proliferation bioassay.
authors.affiliation: Department of Biological Sciences, Monsanto Co., Chesterfield, MO 63198.
authors.forename: E Y
authors.initials: EY
authors.lastname: Wong
authors.forename: R
authors.initials: R
authors.lastname: Seetharam
authors.forename: C E
authors.initials: CE
authors.lastname: Kotts
authors.forename: R A
authors.initials: RA
authors.lastname: Heeren
authors.forename: B K
authors.initials: BK
authors.lastname: Klein
authors.forename: S R
authors.initials: SR
authors.lastname: Braford
authors.forename: K J
authors.initials: KJ
authors.lastname: Mathis
authors.forename: B F
authors.initials: BF
authors.lastname: Bishop
authors.forename: N R
authors.initials: NR
authors.lastname: Siegel
authors.forename: C E
authors.initials: CE
authors.lastname: Smith
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D005796:Genes; D005813:Genes, Synthetic; D005822:Genetic Vectors; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D013002:Somatomedins / Q000235:genetics*
chemical_list: D011993:Recombinant Fusion Proteins; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I