Fig. 3. A novel experimental system to quantitatively determine FGF-2 export from living CHO cells. CHO_FGF-2-GFP cells were grown for 18 hours at 37°C under the conditions indicated followed by dissociation from the culture plates by using a protease-free protocol. The cell suspension was then processed for the FACS analysis under the conditions indicated. Panels A-E represent dot blots where total GFP-derived fluorescence was blotted against cell surface-derived PE fluorescence. (A) Cells grown in the absence of doxicyclin. (B) Cells grown in the presence of doxicyclin and processed with anti-GFP antibodies. (C) Cells grown in the presence of doxicyclin and processed with anti-GFP antibodies. (D) Cells grown in the presence of doxicyclin followed by a wash procedure using a heparin-containing buffer and antibody processing. (E) Cells grown in the presence of doxicyclin followed by trypsin digestion and antibody processing. Panels F and G represent the corresponding histograms of GFP-derived fluorescence and PE-derived cells surface fluorescence, respectively. The colours correspond to the conditions shown in panels A-E.