Fig 6. Fluorescence images of GFP-expressing PC12 cells.

PC12 cells were transfected with 1 μg enhanced GFP plasmid DNA in 35 mm dishes using Lipofectamine 2000. Green fluorescence images were taken (34.8x magnification, 1/3 second exposure time, scale bars = 50 μm). In (A), the cells were maintained at 37°C, whereas in (B) the cells were transferred to 33°C on day 2. The images were taken at 96 hours after transfection. The percentage of the green cells was ~2% and ~6% for (A) and (B), respectively. In (C), when the cells were trypsinized during the passage or one day before transfection, the percentage of green cells was ~18%. As the comparison, the cells in (B) were not trypsinized. Like the cells in (B), the cells in (C) were also transferred to 33°C one day later.