Illustration of the hTERT reporter and control adenoviral vector. (A) The hTERT reporter adenoviral vector. In this vector, the dGFP expression cassette driven by the hTERT promoter (–576 to +30 of the hTERT gene sequence) was engineered in the E1 region. The expression cassette was shielded by the chicken β-like globin gene insulator for ensuring specificity of the hTERT promoter.³⁸  (B) The control Ad5F35-GFP vector encoding GFP under the control of the constitutively active PGK1 promoter has been described previously.^33,36  Both vectors are fiber-retargeted Ad5F35 vectors.