Localisation of the effects of HPV 16 oncogenes on the human IVL promoter. (A) Schematic representation of reporter constructs containing different parts of the human IVL promoter. The IVL promoter fragments were cloned in the reporter vector pGL3 in front of the luciferase gene. Nucleotide positions are given relative to the transcription start site. Selected transcription factor recognition sites are indicated (C/EBP, CCAAT enhancer binding protein). (B) The effect of differentiation on the transcriptional activity of constructs containing different fragments of the IVL promoter in human foreskin keratinocytes. HFK cells were co-transfected with pGL3 luciferase reporter constructs containing different fragments of the human IVL promoter (IVL-2418, IVL-1809, IVL-744, IVL-272) along with pcDNA control vector. Cells were left in serum-free medium or induced to differentiate in DMEM with serum and high calcium. (C) and (D) The effect of HPV 16 E6 or E7 oncogenes on the transcriptional activity of constructs containing different fragments of IVL promoter in proliferating (C) or in differentiating (D) HFK cells. HFK cells were co-transfected with pGL3 luciferase reporter constructs along with either control vector (pcDNA) or expression constructs encoding HPV16 E6 or E7. The luciferase activities are shown relative to the activity of cells co-transfected with IVL-2418 reporter construct along with the control vector. Data are from three independent experiments with standard errors shown as error bars.