Figure 4.

E2F-mediated regulation of the RNR1a gene in the UV-C response. (A) LUC activity was measured in mid-log phase BY-2 transgenic cells harbouring the WT (non-hatched bars) or dpE2FMU (hatched bars) promoter constructs. Transgenic cells with the WT (empty bars) or dpE2FMU constructs (fine hatched bars) were taken at 0 and 4 h following UV-C irradiation at 450 J/m². In parallel, control non-irradiated cells harbouring the WT (black bars) or dpE2FMU constructs (large hatched bars) were analysed. Results were reproducible in three individual experiments, error bars are indicated. (B) E2F factor analysis in 6 µg of nuclear extracts from mid-log phase cells which were non-irradiated (C) or taken at 4 h after irradiation (UV-C, 450 J/m²). The protein gel blot was incubated with the antibody directed against the well conserved DBD of human E2F5 factor. Various E2F factors present in the BY-2 cells were detected.