Figure 2.

Conservative Redistribution of Parental Histones to the Periphery of UVC-Damaged Regions

(A) Experimental procedure for measuring parental histone loss and redistribution around the UVC-damaged zone. Microscopy images show fluorescent patches of parental H3.3 (red) before and 15 min after local UVC damage (top) or photo-bleaching (bottom) in U2OS cells stably expressing H3.3-SNAP and GFP-XPC. Scale bar, 5 μm.

(B) Parental H3.3 fluorescence measured in the entire nucleus and in the bleached (red) or damaged zone (purple) 15 min post-laser micro-irradiation is normalized to before laser (dotted line). n, number of cells.

(C) Parental H3.3 fluorescence measured in concentric regions around the UVC (top graph) or bleaching laser impact (bottom graph) at the indicated time points is normalized to the fluorescence in the patch before laser.

(D) Difference in red fluorescence distribution obtained by subtracting 0 min from 15 min values quantified in (C). The positive and negative areas under the UVC curve (purple) are equivalent. The position of the repair zone is based on GFP-XPC accumulation at 15 min. Error bars, SD from n cells scored in two independent experiments.

(E) Interpretation of the results shown in (D): redistribution of old H3.3 histones to the periphery of UVC-damaged regions. Areas were converted to distances.

See also Figures S2 and S3.