We have tried to make a stable CHO cell line transfected with pEGFP-N1
plasmid coding for a GFP fusion protein. 2-3 days after transfection the
GFP emission disappeared but we continued the G418 selection. After 10 d,
surviving cell colonies were isolated. We characterized by PCR the
presence of the transcripts of interest in most of them. However, when we
observed one of these colonies the large majority of the cells were
negative for GFP fluorescence. But surprisingly we could also observed on
the same coverslip very few positive cells for GFP emission. The level of
fluorescence was not strong but well detectable.
Does this result mean that the level of GFP expression is not homogeneous
among cells plated from the same colony ?
Did anybody obtain similar results ?
How could we increase the level of GFP fusion protein expression in stable
cell line?
Many thanks in advance
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Beatrice Marqueze-Pouey
INSERM U 374/464, Institut Federatif Jean Roche, Faculte de Medecine-Nord,
13916 Marseille Cedex 20, France.
Tel (33) 4 91 69 88 32, Fax (33) 4 91 09 05 06,
E-mail: marqueze at jean-roche.univ-mrs.fr
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