FIGURE 5.

A, the Elongin A-CUL5 interaction is not restricted to DNA damage regions. FRET efficiencies were measured at or away from regions of laser microirradiation (n ≥ 18). Cells were allowed to recover for 2, 5, or 15 min after microirradiation. Inset, representative images of Halo-Elongin A in microirradiated cells. Yellow boxes, regions of FRET measurements at or away from sites of laser microirradiation. B, assembly of the Elongin A ubiquitin ligase is independent of PARP activity. AP-FRET was measured 5 min after microirradiation of Hoechst-sensitized U2OS cells that had been treated or not with PARP inhibitor PJ34. Values represent average ± S.E. (error bars) (n = 15). C, Elongin A recruitment to microirradiated regions is not inhibited by PJ34. Kinetics of Elongin A or ALC1 recruitment (n = 15) to microirradiated regions of Hoechst-sensitized U2OS cells, with or without PJ34. Cells were imaged every second, and intensity values were binned over 5-s intervals. Microirradiation was initiated at time = 0 s.