Figure 4

Influence of Ku80 on AP-2α transcriptional activity on ERBB2 gene promoter. (a) Schematic representation of the reporter vectors used in this study. All the reporter vectors contain 86 bp of the ERBB2 core promoter. The black diamond indicates the CAAT box; the black triangle the TATA box. The sequence of the AP2BS is that of AP-2 binding sites located at -512 bp from the main ERBB2 transcription start site. Mutation of three nucleotides abrogates the binding of the transcription factor to AP2BSmut [25]. (b) Variation of luciferase activity in cells transfected with (+) AP-α expression vector alone or with the Ku80 expression vector, in HCT116 and in 70/32 (HCT116 Ku80+/-) cell lines; compared with the activity in the cells transfected with the corresponding empty expression vectors (-). (c) Western blot showing the levels of AP-2α and Ku80 proteins in the cells transfected with the corresponding expression vectors.