Fig. 3. Binding kinetics of DDB2 after local UV irradiation. (A) Example of a DDB2-EYFP cell that shows local accumulation after local UV-C irradiation with 100 J/m² through 5 µm pores at 37°C. (B) Example of a HeLa cell expressing EGFP-CUL4A and (C) an XP-C cell expressing DDB2-EYFP. Both fusion proteins accumulate after local UV-C irradiation through 5 µm pores at 37°C (B,C). (D) Quantification of accumulation kinetics of DDB2-EYFP in MRC5 cells (brown line, n=9), EYFP-DDB2 in MRC5 cells (green line, n=8), DDB2-EYFP in XP-C cells (red line, n=3) and EGFP-CUL4A in HeLa cells (blue line, n=3). Curves were normalized to the plateau value. Time point t=0 is defined as the start of UV irradiation. (E) Quantification of assembly kinetics of DDB2-EYFP at 37°C (red, n=9) and 27°C (blue, n=8). The local accumulation of DDB2-EYFP was measured and plotted as a percentage of the total EYFP fluorescence in the cell nucleus. The error bars represent the standard deviation.