Isolation of a protein from bovine brain which promotes neurite extension from chick embryo cerebral cortex neurons in defined medium.
Seven-day-old chick embryo cerebral cortex neurons cultured at low density (10,000 cells/16 mm well) in defined medium in polylysine-coated wells fail to extend neurites and assume a flattened phase-dark morphology. Addition of soluble bovine brain extract promotes neurite outgrowth and rounding of the cell body (which becomes phase-bright). A quantitative bioassay was utilized to purify this neurite extension factor (NEF), based on counting the number of phase-bright neurons with processes at least equal to one cell body diameter after 20 h in culture. Using a combination of heat treatment, DEAE-cellulose chromatography, and gel filtration, an acidic protein with a native Mr = 75,000 has been purified. Upon reduction it yields subunits of Mr = 37,000. Purified fractions are active at 100 ng/ml in inducing neurite outgrowth in this bioassay.
D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology*; D001681:Biological Assay; D002417:Cattle; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D002642:Chick Embryo; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000302:isolation & purification* / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*
D009419:Nerve Tissue Proteins