title: Long-term, stable expression of green fluorescent protein in mammalian cells.
abstract: Despite the proven utility of green fluorescent protein (GFP) as a reporter molecule for transient gene expression, the adequacy of this marker for models requiring durable, high-level gene expression has not been fully tested. To address this issue, we performed the transfection of Chinese Hamster Ovary (CHO) cells with plasmid DNA encoding both GFP and neomycin phosphotransferase (neo) cassettes. The expression of GFP was measured after the cells were cultured in the presence or absence of G418-mediated selective pressure. After removal of G418 from the growth medium, the percentage of pooled G418 resistant transfectants which co-expressed the GFP transgene increased or remained unchanged. Flow cytometric and visual isolation of GFP-expressing cells was possible without continued selection in G418. One cloned cell line, C463, maintained high-level green fluorescence for 18 weeks in G418 and an additional 12 weeks in nonselective medium. Our data suggest expression of GFP does not confer a growth disadvantage in mammalian cells.
authors.affiliation: Laboratory of Chemical Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: A N
authors.initials: AN
authors.lastname: Gubin
authors.forename: B
authors.initials: B
authors.lastname: Reddy
authors.forename: J M
authors.initials: JM
authors.lastname: Njoroge
authors.forename: J L
authors.initials: JL
authors.lastname: Miller
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D004351:Drug Resistance; D005839:Gentamicins / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection
chemical_list: D005839:Gentamicins; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; C010680:antibiotic G 418