title: Biosynthesis and cocoon-export of a recombinant globular protein in transgenic silkworms.
abstract: A gene construct was made by fusing the coding sequence of the red fluorescent protein (DsRed) to the exon 2 of the fibrohexamerin gene (fhx), that encodes a subunit of fibroin, the major silk protein of the silkworm Bombyx mori. The fusion gene was inserted into a piggyBac vector to establish a series of transgenic lines. The expression of the transgene was monitored during the course of larval life and was found restricted to the posterior silk gland cells as the endogenous fhx gene, in all the selected transgenic lines. The exogenous polypeptide was secreted into the lumen of the posterior silk gland together with fibroin, and further exported with the silk proteins as a foreign constituent of the cocoon fiber. The capacity of DsRed to emit fluorescence in the air-dried silk thread led to show that the recombinant protein was distributed over the whole length of the fiber. A remarkable property of the system lies in the localization of the globular protein at the periphery of the silk thread, allowing its rapid and easy recovery in aqueous solutions, without dissolving fibroin. The procedure represents a novel and promising strategy for the production of massive recombinant proteins of biomedical and pharmaceutical interest, with reduced cost.
authors.affiliation: Unité Nationale Séricicole, INRA, 25 quai J-J Rousseau 69350 La Mulatière, France. croyer@clermont.inra.fr
authors.forename: Corinne
authors.initials: C
authors.lastname: Royer
authors.forename: Audrey
authors.initials: A
authors.lastname: Jalabert
authors.forename: Martine
authors.initials: M
authors.lastname: Da Rocha
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Grenier
authors.forename: Bernard
authors.initials: B
authors.lastname: Mauchamp
authors.forename: Pierre
authors.initials: P
authors.lastname: Couble
authors.forename: Gérard
authors.initials: G
authors.lastname: Chavancy
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified / Q000378:metabolism*; D012831:Bombyx / Q000235:genetics*; D005349:Fibroins / Q000096:biosynthesis / Q000235:genetics*; D015870:Gene Expression; D005822:Genetic Vectors; D006023:Glycoproteins / Q000096:biosynthesis / Q000235:genetics*; D007814:Larva; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D011679:Pupa; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis*; D047011:Silk / Q000096:biosynthesis*; D015533:Transcriptional Activation; D019076:Transgenes / Q000235:genetics / Q000502:physiology; D000097573:Red Fluorescent Protein
chemical_list: D005349:Fibroins; D006023:Glycoproteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D047011:Silk; D000097573:Red Fluorescent Protein; C418613:fhx protein, Bombyx mori