Figure 2

Regulational expression of eGFP by the novel Tet-On system. HEK293 cells were transfected with different inducible expression systems as indicated and were maintained in the presence or absence of 2 μg Dox/ml. pCMV-eGFP and pAd5-E1 were used as positive and negative controls, respectively. Forty-eight hours after transfection, images were taken with a fluorescent microscope (200 × view field).